Effects of thinning on the understory light environment of different stands and the photosynthetic performance and growth of the reforestation species Phoebe bournei

Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the understory.In this study,we selected three stands typical in south China(a Cryptomeria japonica plantation,a Quercus acutissima plantation,and a mixed stand of both)and three thinning intensities to determine the best understory light environ-ment for 3-year-old Phoebe bournei seedlings.The canopy structure,understory light environment,and photosynthe-sis and growth indicators were assessed following thin-ning.Thinning improved canopy structure and understory light availability of each stand;species composition was the reason for differences in the understory light environ-ment.Under the same thinning intensity,the mixed stand had the greatest light radiation and most balanced spectral composition.P.bournei photosynthesis and growth were closely related to the light environment;all three stands required heavy thinning to create an effective and sustained understory light environment.In a suitable understory light environment,the efficiency of light interception,absorption,and use by seedlings was enhanced,resulting in a higher carbon assimilation the main limiting factor was stomatal conductance.As a shade-avoidance signal,red/far-red radia-tion is a critical factor driving changes in photosynthesis and growth of P.bournei seedlings,and a reduction increased light absorption and use capacity and height:diameter ratios.The growth advantage transformed from diameter to height,enabling seedlings to access more light.Our findings suggest that the regeneration of shade-tolerant species such as P.bournei could be enhanced if a targeted approach to thinning based on stand type was adopted.

Effects of Fresh Cupressus sempervirens Leaves Infusion on Growth Performance, Intestinal Microbiota and Haemato-Biochemical Parameters in Broilers

The accumulation of growth-promoting antibiotic residues in animal products and the resistance developed by bacteria in poultry farms has led to a search for natural compounds derived from plants. This study was designed to promote the production performance of broiler chickens using fresh Cupressus sempervirens leaves infusion. Fresh Cupressus sempervirens leaves were harvested, washed, chopped and ground to a paste using a blender and fermented for three days in a closed container at a rate of 500 g/L of water. The solution obtained was filtered and added at the rate of 2, 4, 6, 8 and 10 ml/L of drinking water. The chickens fed on the graded level of the solution were compared to a control ration without an additive and positive control group supplemented with 1 g antibiotic/kg feed. At the finisher phase and throughout the study period, water intake increased significantly (P < 0.05) with increasing levels of infusion. Feed intake decreased significantly (P < 0.05) with 2 and 4 ml of infusion/L drinking water. Live weight and weight gain were significantly (P < 0.05) higher with 6 ml/L, while feed conversion significantly (P < 0.05) decreased with the same treatment compared with the control treatment without additives (T0). Carcass characteristics were not significantly (P > 0.05) affected by the inclusion of Cupressus sempervirens infusion. Haematological parameters significantly (P < 0.05) increase independently of the rate of incorporation of the infusion into the drinking water, with the exception of RBCs, MCHT and PCT. Serum content in total protein, globulins, LDL cholesterol and triglycerides were significantly (P < 0.05) high with 8 and 10 ml Cupressus sempervirens infusion/litre drinking water as compared to all other treatments. AST, ALT, urea, creatine, albumin, total cholesterol and HDL-cholesterol were not significantly affected. The lactic acid bacteria load increased significantly (P E. coli and salmonella counts decreased significantly (P < 0.05) with infusion compared to the control without additive. In conclusion, 6 ml of Cupressus sempervirens infusion can be used as an alternative to antibiotic feed additives to promote growth performance in broilers.

Effect of Using Israel Napier Grass in Feed Ration on Growth Performance of Local Chicken of Cambodia

This study investigated the effect of Israel grass in feed formulation on growth performance of local chicken.The study was conducted from October 2023 until January 2024 in Kampong Chheutel Institute of Technology.The CRD(Completely Randomized Design)was used with 4 treatments and 4 replications.The local chicks were purchased from local famer at 1 day old and kept in whole pen by feeding commercial feed.At 21 days old the total 320 chicks were allocated into experimental treatments.The 4 feed formulas based on the level of Israel grass added such as 0,5%,7%and 9%,were called T1(control),T2,T3 and T4 respectively.The result showed that body weight gain,feed intake,ADG(Average Daily Gain)and FCR(Feed Conversion Ratio)in all treatments were not significantly different(p>0.05).However,there was strong correlation between living weight with carcass of al treatments,but no difference among carcass percentage of local chicken for all different diet in this study.In conclusion,the Israel grass did not affect growth performance of local chickens and can be used to replace some expensive feed ingredient,such as rice bran.

Supranutrition of microalgal docosahexaenoic acid and calcidiol improved growth performance,tissue lipid profiles,and tibia characteristics of broiler chickens

Background Docosahexaenoic acid(DHA)and calcidiol could be enriched in chicken for improving public nutrition and health.It remains unclear if supranutritional levels of DHA and calcidiol impair growth performance or metabolism of broiler chickens.This study was to determine singular and combined effects of high levels of supplemental DHA-rich microalgal biomass or oil and calcidiol on growth performance,concentrations of triglycerides,cholesterol,and nonesterfied fatty acids in plasma,liver,breast,and thigh,and biophysical properties of tibia.Methods In Exp.1,144 day-old Cornish chicks were divided into 4 groups(6 cages/treatment,6 birds/cage),and were fed a corn-soybean meal basal diet(BD),BD+10,000 IU calcidiol/kg(BD+Cal),BD HA),and BD+1%DHA-rich Aurantiochytrium(1.2 g DHA/kg;BD+D+Cal+DHA for 6 weeks.In Exp.2,180 day-old chicks were divided into5 groups,and were fed:BD,BD+DHA(0.33%to 0.66%oil,1.5 to 3.0 g DHA/kg),BD EPA/kg),BD+DHA+EPA(1.9%to 3.8%eicosapentaenoic acid-rich Nannochloropsis sp.CO18,0.3 to 0.6 g BD+DHA+calcidiol(6000 to 12,000 IU/kg diet),and+DHA+EPA+Cal for 6 weeks.Results Birds fed BD+Cal diet in Exp.1 and BD lower(P+DHA<0.05)+EPA diet in Exp.2 had higher(P<0.05)body weight gain(10%-11%)and gain:feed ratio(7%),and total cholesterol and triglyceride concentrations in plasma(18%-54%),liver(8%-26%),breast(19%-26%),and thigh(10%-19%),respectively,over the controls.The two diets also improved(P<0.05)tibial breaking strength(8%-24%),total bone volume(2%-13%),and(or)bone mineral density(3%-19%)of chickens.Conclusion Supranutrition of dietary calcidiol and DHA alone or together did not produce adverse effects,but led to moderate improvements of growth performance,lipid profiles of plasma and muscle,and bone properties of broiler chickens.

Feeding broiler chickens with arginine above recommended levels:effects on growth performance,metabolism,and intestinal microbiota

Background Arginine is an essential amino acid for chickens and feeding diets with arginine beyond the recommended levels has been shown to influence the growth performance of broiler chickens in a positive way.Nonetheless,further research is required to understand how arginine supplementation above the widely adopted dosages affects metabolism and intestinal health of broilers.Therefore,this study was designed to assess the effects of arginine supplementation(i.e.,total arginine to total lysine ratio of 1.20 instead of 1.06-1.08 recommended by the breeding company) on growth performance of broiler chickens and to explore its impacts on the hepatic and blood metabolic profiles,as well as on the intestinal microbiota.For this purpose,630 one-day-old male Ross 308 broiler chicks were assigned to 2 treatments(7 replicates each) fed a control diet or a crystalline L-arginine-supplemented diet for 49 d.Results Compared to control birds,those supplemented with arginine performed significantly better exhibiting greater final body weight at D49(3778 vs.3937 g;P < 0.001),higher growth rate(76.15 vs.79.46 g of body weight gained daily;P < 0.001),and lower cumulative feed conversion ratio(1.808 vs.1.732;P < 0.05).Plasma concentrations of arginine,betaine,histidine,and creatine were greater in supplemented birds than in their control counterparts,as were those of creatine,leucine and other essential amino acids at the hepatic level.In contrast,leucine concentration was lower in the caecal content of supplemented birds.Reduced alpha diversity and relative abundance of Firmicutes and Proteobacteria(specifically Escherichia coli),as well as increased abundance of Bacteroidetes and Lactobacillus salivarius were found in the caecal content of supplemented birds.Conclusions The improvement in growth performance corroborates the advantages of supplementing arginine in broiler nutrition.It can be hypothesized that the performance enhancement found in this study is associated with the increased availability of arginine,betaine,histidine,and creatine in plasma and the liver,as well as to the ability of extra dietary arginine to potentially ameliorate intestinal conditions and microbiota of supplemented birds.However,the latter promising property,along with other research questions raised by this study,deserve further investigations.

Potential roles of the rectum keystone microbiota in modulating the microbial community and growth performance in goat model

Background Ruminal microbiota in early life plays critical roles in the life-time health and productivity of ruminant animals.However,understanding of the relationship between gut microbiota and ruminant phenotypes is very limited.Here,the relationship between the rectum microbiota,their primary metabolites,and growth rate of a total of 76 young dairy goats(6-month-old)were analyzed,and then 10 goats with the highest or lowest growth rates respectively were further compared for the differences in the rectum microbiota,metabolites,and animal’s immune parameters,to investigate the potential mechanisms by which the rectum microbiota contributes to the health and growth rate.Results The analysis of Spearman correlation and microbial co-occurrence network indicated that some keystone rectum microbiota,including unclassified Prevotellaceae,Faecalibacterium and Succinivibrio,were the key modulators to shape the rectum microbiota and closely correlated with the rectum SCFA production and serum IgG,which contribute to the health and growth rate of young goats.In addition,random forest machine learning analysis suggested that six bacterial taxa in feces could be used as potential biomarkers for differentiating high or low growth rate goats,with 98.3%accuracy of prediction.Moreover,the rectum microbiota played more important roles in gut fermentation in early life(6-month-old)than in adulthood stage(19-month-old)of goats.Conclusion We concluded that the rectum microbiota was associated with the health and growth rate of young goats,and can be a focus on the design of the early-life gut microbial intervention.

Growth performance,nutrient digestibility,intestinal morphology,cecal mucosal cytokines and serum antioxidant responses of broiler chickens to dietary enzymatically treated yeast and coccidia challenge

Background There is a growing search for natural feed additives to alleviate the deleterious effects of coccidia infection in poultry production.This study aimed to investigate the effect of enzymatically treated yeast(ETY) on the growth performance,nutrient digestibility,intestinal morphology,antioxidative status,and cecal mucosa cytokines of coccidia-challenged broiler chickens.Methods From d 1 to 14 post hatching,480 broiler chickens were allocated to 3 corn-soybean meal-based experimental diets with increasing concentrations of ETY(0,1,or 2 g/kg).The experiment was designed as a randomized complete block design with body weight(BW) used as a blocking factor.On d 14 post hatching,the birds were re-randomized within each of the 3 experimental diets.Each of the 3 diet groups was split into a challenge or no-challenge group.This resulted in a 3 × 2 factorial arrangement of treatments.The coccidia challenge was administered on d 15 by an oral gavage.Results Dietary ETY improved(P < 0.05) the G:F of birds on d 21 regardless of the challenge state and linearly increased(P < 0.01) the apparent ileal digestibility of dry matter(DM),nitrogen,and gross energy(GE).The coccidia challenge decreased(P < 0.05) BW gain and feed intake of broiler chickens and reduced(P < 0.01) the total tract retention of DM,GE,and nitrogen.The coccidia challenge increased(P < 0.01) the mRNA gene expression of TNFα,IL-1β,IL-10,and IL-6 in the cecal mucosa.There was a tendency(P ne = 0.08) for ETY to linearly reduce IL-1β expression.Additionally,ETY supplementation increased(P < 0.05) the geexpression of OCLN.Serum catalase increased(P < 0.05) with dietary ETY in broiler chickens on d 21.Dietary ETY linearly increased(P < 0.05) the ileal villus height to crypt depth ratio,and ileal goblet cell density in broiler chickens.The ileal and excreta oocyst counts decreased(P < 0.01) with increasing supplementation of dietary ETY in coccidia-challenged broiler chickens on d 21.Conclusions Dietary ETY enhanced nutrient utilization and augmented intestinal development in broiler chickens.However,dietary ETY did not completely attenuate the adverse effects of a coccidia challenge in broiler chickens.

Growth Performance of Complete Diallel Crosses Among New Varieties of Chinese Pearl Oyster Pinctada martensii

Pinctada martensii is an important shellfish for the production of sea pearls in China.To improve the growth performance of P.martensii,we successfully established three complete diallel crosses using three new varieties of P.martensii,which were named Haiyou No.1,Haixuan No.1,and Nanke No.1,to investigate the growth performance of each self-cross line and hybrid line in Beihai,Guangxi Zhuang Autonomous Region,China.Generally,high fertilization and hatching rates were observed in the experiment,suggesting that there was no sperm-egg recognition barrier among these three P.martensii varieties.The survival rate of the self-cross lines was relatively higher than that of hybrid lines,and♀‘Haixuan No.1’×♂‘Haiyou No.1’maintained a high survival rate during the grow-out stage.The shell length and width were affected by the genotypes as well as the interaction between the genotypes and environmental factors on day 400.The variances of the general combining abilities(GCA)and specific combining abilities(SCA)for shell length and width were the result of both additive genetic variance and nonadditive genetic variance.When Haixuan No.1 was the female parent and Nanke No.1 was the male parent,the GCA for shell length and width were both positive on day 400.The heterosis of Haixuan No.1 and Nanke No.1 in terms of shell length and width was positive.From the resulting combining ability and heterosis,♀‘Haixuan No.1’×♂‘Nanke No.1’was considered an ideal hatchery method to improve the growth performance of P.martensii.Our results therefore demonstrated that crossbreeding among these three new varieties can further improve the growth performance of P.martensii.

Sex effect on growth performance and marker-aided sex discrimination of seedlings of Populus deltoides

Sex has a significant effect on various traits among dioecious plants.In this analysis of the sex effect on the radial growth and wood density of numerous 20-yearold trees of Populus deltoides growing in a common garden,male trees performed better than the females in radial growth,but sex did not significantly affect wood density.Growth rate and wood density were weakly negatively correlated.Sex selection is also critical for controlling seed-hair pollution from P.deltoides plantations.However,because the juvenile period of P.deltoides lasts for years,a reliable technique to determine the sex of juveniles has been needed.Here we developed a marker-aided technique to discriminate the sexes of P.deltoides seedlings.This study provides essential information on target traits and a highly desirable genetic toolkit for accelerate breeding programs for this important tree species.

Impacts of dietary supplementation of bamboo vinegar and charcoal powder on growth performance,intestinal morphology,and gut microflora of large-scale loach Paramisgurnus dabryanus

Although accumulating data demonstrate that dietary supplementation of bamboo vinegar and charcoal powder(BVC)can significantly strengthen the immunity and boost the growth of domestic animals,its application potency still awaits verification in commercial fish species such as the large-scale loach Paramisgurnus dabryanus.The impacts of 90-day dietary supplementation of 1%and 2%BVC on survival and growth performance of the loach,and on the intestinal morphological characteristics and gut microflora were analyzed.Our data show that the large-scale loach supplied with BVC at the experimental doses had significant higher survival rates and better growth performance(indicated by greater weight gain(1.13–1.14 times),higher specific growth rate(1.04 times),and lower feed conversion ratio(0.88–0.89 times))compared to that of the control(P<0.05).Histological examination revealed significant longer villus(3.22–5.54 times),deeper crypt(1.77–1.87 times),and thicker muscle(1.59–3.17 times)in the intestines of large-scale loach fed with BVC(P<0.05).Furthermore,we found that the gut microflora consisted of significantly fewer proportions of potential pathogenic bacterial species(Aeromonas veronii and Escherichia coli),but significantly greater proportions of beneficial microbes(Lactococus raffinolactis and Faecalibacterium prausnitzii).Therefore,dietary intake of BVC can promote intestinal tract development and optimize gut microflora,by which the survival and growth of large-scale loach may be improved.

Effect of dioscorea opposite waste on growth performance, blood parameters, rumen fermentation and rumen bacterial community in weaned lambs

This study investigated the effects of dioscorea opposite waste(DOW) on the growth performance, blood parameters, rumen fermentation and rumen microbiota of weaned lambs. Sixty healthy weaned Small-Tailed Han lambs(male,(22.68±2.56) kg initially) were used as the experimental animals. Four levels of concentrate: 0(control, CON), 10%(DOW1), 15%(DOW2) and 20%(DOW3), were replaced with DOW in the basal diet as experimental treatments. The results showed that lambs fed the DOW2 diet had a higher(P<0.05) dry matter intake(DMI) than the other groups. There was no significant difference(P>0.05) among DOW groups in average daily weight gain(ADG), and replacing concentrate with DOW linearly or quadratically increased(P<0.05) the ADG, while lambs fed the DOW2 diet showed greater(P<0.05) ADG than the CON group. The relative plasma concentration of growth hormone(GH), insulin like growth factor-1(IGF-1) and insulin were affected by DOW, replacing concentrate with DOW linearly or quadratically(P<0.05) enhanced the plasma concentration of GH, IGF-1 and insulin, which was significantly higher(P<0.05) in the DOW2 group than in the CON, DOW1 and DOW3 groups. In addition, the DOW treatment showed a lower(P<0.05) concentration of blood urea nitrogen(BUN) than the CON group. Replacing concentrate with DOW quadratically decreased(P<0.05) the ruminal ammonia nitrogen(NH3-N) and increased(P<0.05) the total of volatile fatty acids(TVFAs) at 0 and 4 h after feeding as well as linearly decreased(P<0.05) the NH3-N at 8 h after feeding. Replacing concentrate with DOW linearly decreased(P<0.05) the propionate and increased the aceate before feeding, and linearly decreased(P<0.05) propionate and quadratically increased(P<0.05) the aceate at 4 and 8 h after feeding. Lambs fed the DOW2 diet increased the phylum Firmicutes and genera Succiniclasticum and Ruminococcus_1 groups, whereas decreased(P<0.05) the relative abundance of phylum Deferribacteres and genera intestinimonas and Ruminiclostridium. In summary, replacing the concentrate with 15% DOW was beneficial for improving the rumen fermentation and ADG by increasing the DMI and modulating the rumen microbial community.

Effects of Maize Silage Harvest Stage on Growth Performance and Economic Benefits of Beef Cattle

[Objectives]This study aimed to investigate the effects of whole-crop maize silage harvested at different stages on growth and economic benefits of beef cattle.[Methods]A total of 30 Simmental crossbred cattle weighing about 378 kg were randomly divided into three groups,respectively fed for 70 days with whole-crop maize silage harvested at milk stage(GroupⅠ),dough stage(GroupⅡ)and physiological maturity stage(GroupⅢ).Moreover,the cattle in all groups were given the same concentrate diet.[Results]There were significant differences in dry matter,crude protein and neutral detergent fiber between whole-crop maize silages harvested at different stages(P<0.05).The dry matter in GroupⅡandⅢwas significantly higher than that in GroupⅠ(P<0.05).The crude protein content peaked in GroupⅡ,up to 6.37%,which was significantly higher than that in GroupⅠ(by 12.74%,P<0.05)and GroupⅢ(by 9.26%,P<0.05).Starch content significantly increased with the postponing of maize harvest(P<0.05).The content of neutral detergent fiber in Group I was significantly higher than that in GroupⅡ(P<0.05)and GroupⅢ(P<0.05).The average daily weight gain in GroupⅡwas 8.53%higher than that in GroupⅠ(P<0.05)and 3.70%higher than that in GroupⅢ(P>0.05).The dry matter intake in GroupⅡwas significantly higher than that in GroupⅠ(P<0.05)and GroupⅢ(P<0.05).There was no significant difference in feed/gain ratio between the groups(P>0.05).The economic benefit in GroupⅡwas the highest,up to 9.99 yuan/day per capita.,followed by that in GroupⅢ,9.79 yuan/day per capita,and that in GroupⅠwas the lowest,only 8.03 yuan/day per capita.[Conclusions]The whole-crop maize silage harvested at dough stage has the best quality and produces the highest economic returns for beef cattle.

Effects of Whole-plant Corn Silage and Whole-plant Wheat Silage on Growth Performance and Economic Benefits of Beef Cattle

[Objectives]This study was conducted to study the effects of whole-plant corn silage and whole-plant wheat silage on growth performance and economic benefits of beef cattle.[Methods]Thirty Simmental crossbred cattle were selected and randomly divided based on their weight into two groups,15 cows in each group,with an average weight of 398 kg.Each group was fed the same concentrated feed,and the whole-plant corn silage and wheat silage were fed as roughage feed,respectively.The experimental period was 90 d.[Results](1)There was no significant difference in the initial weight of beef cattle between test group 1 and test group 2(P>0.05).Compared with group 2,group 1 had a higher final weight,average daily gain,and dry matter intake of beef cattle,without significant differences(P>0.05).Group 1 was 0.58%,1.99%,and 1.43%higher than group 2,respectively.The feed-to-gain ratio of test group 1 decreased by 0.54%compared with test group 2(P>0.05),with no significant difference therebetween.(2)The economic benefit of group 1 was 11.45 yuan/(day·capita),while the economic benefit of group 2 was 2.41 yuan/(day·capita),and group 1 was 9.04 yuan/(day·capita)higher than group 2.[Conclusions]Whole-plant corn silage for feeding beef cattle has the advantages of good weight gain and low breeding cost,and can be popularized in beef cattle fattening.

Parkia biglobosa (Jacq.) R. Br. Ex G. Don Fruit Pulp Supplementation in the Diet of Local Chickens in Burkina Faso: Effects on Growth Performance and Carcass Characteristics

This work aimed to evaluate the effects of supplementation of Parkia biglobosa fruit pulp flour in the CPAVI chicken ration on the growth performance and carcass characteristics of local chickens. This study involved 50 local chicks of eight weeks of age. Chickens were divided into 5 groups of 10 chicks corresponding to five experimental rations containing 0%, 1%, 2%, 3% and 4% pulp from fruits of P. biglobosa. The nutritional composition of P. biglobosa fruit pulps were analyzed, then growth parameters and carcass characteristics were measured. The results showed that the fruit pulps of P. biglobosa were rich in metabolizable energy (4015.02 ± 0.21 Kcal/kg), crude fiber (16.88% ADF and 19.81% NDF) and potassium (2.45% ± 0.01%). Thus, the group of local chickens fed the diet containing 1% supplementation had a significantly higher live weight (1200.85 g) and carcass yield (91.99 g) (P supplementation. Additionally, individual feed consumption and average daily gain of the group at 1% supplementation were higher. In short, the flour from the pulp of the fruit of Parkia biglobosa can be supplemented up to 1% in the CPAVI pullet type feed for local chickens.

Effects of Replacing Maize with Dioscarea bulbifera Flour on Growth Performance of Broiler Chickens

The present study was designed to evaluate Dioscarea bulbifera flour as potential feed ingredient in broilers diets. For this purpose, 256-day-old Cobb 500 broiler chicks, were divided into 4 groups replicated 4 times in a completely randomized design. A control ration (R0) containing maize as the main energy source was compared to three other rations in which 50%, 75% and 100% maize were substituted with Dioscarea bulbifera flour. The main results showed that, the increasing rate of Dioscarea bulbifera flour had no significant (p > 0.05) effect on the digestibility of feed components. Feed intake was higher with 50% and 75% Dioscarea bulbifera flour inclusion levels. As compared to the control ration, a significant (p < 0.05) drop in live weight and weight gain was recorded with 50% substitution while feed conversion ratio increased significantly with increasing level of Dioscarea bulbifera flour in the ration. Dioscarea bulbifera flour induced a linear and significant (p < 0.05) increase in the relative weight of the gizzard, liver and production cost. It was concluded that, substituting 50% maize with Dioscarea bulbifera flour could be a sustainable solution to palliate the growing inflation of maize as animal feed ingredient. However, the incorporation level of Dioscarea bulbifera as feed ingredient in substitution of maize must not exceed 50% at the risk of depreciating growth performance of broilers.

Silage Fermentation Technology and Its Effects on Growth Performance of Local Pigs

This paper first introduced the silage fermentation technology,including the selection of strains and activation expansion technology,the screening of high-quality fermentation raw materials,and the comparative experiment of fermentation process.It discussed feeding methods for sows and growing-finishing pigs at different breeding stages.In addition,it analyzed the effects of fermented silage on the growth performance of local pigs at various stages.Finally,it is concluded that silage fermentation can improve the water retention performance of pork,improve the quality of pork from local pigs,increase economic benefits,and achieve the purpose of saving costs and increasing efficiency.

Effects of dietary protein/energy ratio on growth performance,carcass trait,meat quality,and plasma metabolites in pigs of different genotypes

Background： The protein/energy ratio is important for the production performance and utilization of available feed resources by animals. Increased protein consumption by mammals leads to elevated feed costs and increased nitrogen release into the environment. This study aimed to evaluate the effects of dietary protein/energy ratio on the growth performance, carcass traits, meat quality, and plasma metabolites of pigs of different genotypes. Methods： Bama mini-pigs and Landrace pigs were randomly assigned to two dietary treatment groups （Chinese conventional diet with low protein/energy ratio or National Research Council diet with high protein/energy ratio; n = 24 per treatment） in a 2 x 2 factorial arrangement. Blood and muscle samples were collected at the end of the nursery, growing, and finishing phases. Results： We observed significant interactions （P 〈 0.05） between breed and diet for total fat percentage, intramuscular fat （IMF） content, protein content in biceps femoris （BF） muscle, and plasma urea nitrogen （UN） concentration in the nursery phase; for average daily gain （ADG）, average daily feed intake （ADFI）, dry matter, IMF content in psoas major （PM） muscle, and plasma total protein and albumin concentrations in the growing phase; and for drip loss and plasma UN concentration in the finishing phase. Breed influenced （P 〈 0.05） growth performance, carcass traits, and meat quality, but not plasma metabolites. Throughout the trial, Landrace pigs showed significantly higher （P 〈 0.0_5） ADG, ADFI, dressing percentage, lean mass rate, and loin-eye area than did Bama mini-pigs, but significantly lower （P 〈 0.0.5） feed/gain ratio, fat percentage, backfat thickness, and IMF content. Dietary protein/energy ratio influenced the pH value, chemical composition of BF and PM muscles, and plasma activities of glutamic-pyruvic transaminase and gamma-glutamyl transpeptidase, and plasma concentration of UN. Conclusions： Compared with Landrace pigs, Bama mini-pigs showed slower growth and lower carcass performance, but had better meat quality. Moreover, unlike Landrace pigs, the dietary protein/energy ratio did not affect the growth performance of Bama mini-pigs. These results suggest that, in swine production, low dietary protein/energy ratio may be useful for reducing feed costs and minimizing the adverse effects of ammonia release into the environment.

Effect of Glycyrrhiza uralensis Fisch polysaccharide on growth performance and immunologic function in mice in Ural City,Xinjiang

Objective:To discuss the effect of Glycyrrhiza uralensis(G.uralensis) Fisch polysaccharide on growth performance and immunologic function in mice in Ural City,Xinjiang and to provide important data supporting the application of Glycyrrhiza polysaccharide.Methods:A total of100 Kunming mice aged 3 weeks old were randomly divided into 5 groups with 20 mice in each group(10 were females and 10 were males).About 0.5 mL normal saline was given to the mice of control group every day and 0.5 mL G.uralensis Fisch polysaccharide was given to the mice of other groups at the concentration of 1,20,50 and 100 mg/mL respectively.The growth performance(average body weight,average daily feed intake and feed efficiency),immune organ indexes(spleen index and thymus index) and immunologic function(serum IL-2,CD4^+/CD8^+ and the activity of NK cells) of mice in each group were detected continuously.Results:The average body weight,feed efficiency,serum IL-2,CD4^+/CD8^+ and the activity of NK cells of mice were increased with the increase of administrated time after administrating G.uralensis Fisch polysaccharide and were reached up the largest level on Day 28.At the same time,each index was proportional to the given dose and was significantly higher than those of control group and reached up the largest level at the administrated dose of 100 mg/mL.After administrating G.uralensis Fisch polysaccharide,the spleen index and thymus index of mice were increased with the increase of administrated dose and the spleen index and thymus index of mice administrated with the dose of 100 mg/mL were maximum which was more than 1.51 times and 1.43 times of that in control group respectively and the comparative differences showed statistical significance(P<0.05).The average daily feed intake of mice in each group was increased with the passage of lime and at the same time,the comparison of average daily feed intake of mice in each group was not significantly different(P>0.05).Conclusions:G.uralensis Fisch polysaccharide can significantly improve the growth performance and immunologic function of mice and laid a research basis for the clinical application of G.uralensis Fisch polysaccharide.

Effects of dietary supplementation of probiotic,Clostridium butyricum,on growth performance,immune response,intestinal barrier function,and digestive enzyme activity in broiler chickens challenged with Escherichia coli K88

Background： Colibacillosis caused by enterotoxigenic Escherichia coil （E. coil} results in economic losses in the poultry industry. Antibiotics are usually used to control colibacillosis, however, E. coli has varying degrees of resistance to different antibiotics. Therefore the use of probiotics is becoming accepted as an alternative to antibiotics. In this study, we evaluated the effects of Clostfidium butyricum （C. butyficum） on growth performance, immune response, intestinal barrier function, and digestive enzyme activity in broiler chickens challenged with Eschefichia coli （E. coil） K88. Methods： The chickens were randomly divided into four treatment groups for 28 days. Negative control treatment （NC） consisted of birds fed a basal diet without E. coil K88 challenge and positive control treatment （PC） consisted of birds fed a basal diet and challenged with E. coil K88. C. buO/ricum probiotic treatment （CB） consisted of birds fed a diet containing 2 x 107 cfu C. buO/ricum/kg of diet and challenged with E. coil K88. Colistin sulfate antibiotic treatment （CS） consisted of birds fed a diet containing 20 mg colistin sulfate/kg of diet and challenged with E. coil K88. Results： The body weight （BW） and average day gain （ADG） in the broilers of CB group were higher （P 〈 0.05） than the broilers in the PC group overall except the ADG in the 14-21 d post-challenge. The birds in CB treatment had higher （P 〈 0.05） concentration of tumor necrosis factor-a （TNF-a） at 3 and 7 d post-challenge, and higher （P 〈 0.05） concentration of interleukin-4 （IL-4） at 14 d post-challenge than those in the PC treatment group. The concentration of serum endotoxin in CB birds was lower （P 〈 0.05） at 21 d post-challenge, and the concentrations of serum diamine oxidase in CB birds were lower （P 〈 0.05） at 14 and 21 d post-challenge than in PC birds. Birds in CB treatment group had higher （P 〈 0.05） jejunum villi height than those in PC, NC, or CS treatment at 7, 14, and 21 d post-challenge. In comparison to PC birds, the CB birds had lower （P 〈 0.05） jejunum crypt depth during the whole experiment. The birds in CB or CS treatment group had higher （P 〈 0.05） activities of amylase and protease at 3, 7, and 14 d post-challenge, and higher （P 〈 0.05） activity of lipase at 3, 7 d post-challenge than PC birds.

Effects of creep feeding and supplemental glutamine or glutamine plus glutamate (Aminogut) on pre- and post-weaning growth performance and intestinal health of piglets

Background： Creep feeding is used to stimulate piglet post-weaning feed consumption.L-Glutamine（GLN） is an important source of fuel for intestinal epithelial cells.The objective of this study was to determine the impact of creep feeding and adding GLN or AminoGut（AG;containing glutamine ＋ glutamate） to pre-and post-weaning diets on pig performance and intestinal health.Litters（N = 120） were allotted to four treatments during 14–21 d of lactation： 1） No creep feed（NC,n = 45）;2） creep fed control diet（CFCD,n = 45）;3） creep fed 1% GLN（CFGLN,n = 15）;4） creep fed.88% AG（CFAG,n = 15）.After weaning,the NC and CFCD groups were sub-divided into three groups（n = 15 each）,receiving either a control nursery diet（NC-CD,CFCD-CD） or a diet supplemented with either GLN（NC-GLN,CFCD-GLN） or with AG（NC-AG,CFCD-AG）.Litters that were creep fed with diets containing GLN or AG also were supplemented with those amino acids in the nursery diets（CFGLN-GLN,CFAG-AG）.Glutamine was added at 1% in all three post-weaning diet phases and AG was added at.88% in phase 1 and 2 and at.66% in phase 3.Results： Feed conversion（feed/gain） showed means among treatment means close to significance（P = 0.056） and Tukey＇s test for pairwise mean comparisons showed that Pigs in the CFGLN-GLN group had the best feed conversion（feed/gain） in the first three-week period post-weaning,exceeding（P = 0.044） controls（CFCD-CD） by 34%.The NC-AG group had（P = 0.02） the greatest feed intake in the last three week of the study,exceeding controls（CFCD-CD） by 12%.CFGLN-GLN,CFCD-GLN and sow reared（SR） pigs had the greatest（P = 0.049） villi height exceeding the CFCD-AG group by 18%,20% and 19% respectively.The CFAG-AG group had the deepest（P = 0.001） crypts among all treatments.CFGLN-GLN,CFCD-GLN and SR groups had the greatest（P = 0.001） number of cells proliferating（PCNA） exceeding those in the NC-CD group by 43%,54% and 63% respectively.Sow reared pigs showed the greatest（P = 0.001） intestinal absorption capacity for xylose and mannitol.Conclusion： Supplementation of creep feed and nursery diets with GLN and/or AminoGut in the first three week improved feed conversion possibly due to improved intestinal health.