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 soybean meal replacement with fermented alfalfa meal on the growth performance,serum antioxidant functions,digestive enzyme activities,and cecal microflora of geese

Fermented forages are important feedstuffs. Bacillus subtilis inoculants are often used to improve the value of forage legume fermentation. The present work was conducted to study the effects of replacing soybean meal with solid-state fermented alfalfa meal（FAM） with B. subtilis ACCC 01746 on growth performance, serum antioxidant and digestive enzyme activities, and cecal microflora in goose. 300 healthy geese with similar body weights were randomly assigned to six treatment groups with five replicates of 10 geese（five males and five females） each. Geese were fed ad libitum for 35 days. Results showed that the geese fed with 4 and 8% FAM exhibited no significant effects on their final body weights（FBW） and average day gain（ADG）（P〉0.05）, whereas 12% or higher FAM caused poor growth of the geese compared with control diet（linear（L）： P〈0.05）. The average daily feed intake（ADFI）（quadratic（Q）： P〈0.05） and feed conversion ratio（FCR）（L： P〈0.05） with 8% or higher supplementation level were higher than those of the control group. The activities of antioxidant enzyme in serum increased, and the level of malondialdehyde（MDA） significantly decreased with increasing dietary FAM level（L： P〈0.05）. However, no significant differences were observed at 8% or lower supplementation level for glutathione peroxidase（GSH-Px） and superoxide dismutase（SOD）（P〉0.05） and at 4% for catalase（CAT） supplementation level compared with the control group. All diets containing FAM increased digestive enzyme activities in geese. However, geese fed diets with 12% FAM supplementation showed the highest trypsin activities in pancreas（Q： P〈0.05）. Supplementation with 12% or higher FAM significantly increased amylase activities in pancreas（L： P〈0.05） and duodenum（L： P〈0.05） compared with the control group. Significant differences were not observed in total anaerobic bacteria between geese fed with FAM and control diets on day 35（P〉0.05）. The numbers of Bifidobacterium and Lactobacillus in the cecum of geese fed with FAM significantly increased（L： P〈0.05）, but no significant effects were found with 4 and 8% FAM supplementation levels compared with the control（P〉0.05）. By contrast, the coliform counts of cecum decreased with increasing inclusion of FAM, but these counts were significantly reduced in geese fed diets with 12% or higher FAM supplementation level（L： P〈0.05）. Collectively, our results indicated that supplementation of the basal geese diet with 8% FAM had no apparent adverse effects on growth performance, serum antioxidant enzyme activities, and digestive parameters and beneficial microbiota.

Effect of Different Dietary Protein and Lipid Levels on the Growth,Body Composition,and Intestinal Digestive Enzyme Activities of Juvenile Yellow Drum Nibea albiflora(Richardson)

An 8-week feeding trial was conducted to determine the optimal dietary protein-to-lipid ratio for juvenile Nibea albiflora with an initial weight of(11.76 ± 0.20) g.Nine experimental diets containing different concentrations of protein(40%,47%,or 54%) and lipids(5%,9%,or 13%) in a 3 × 3 factorial experimental design were tested in triplicate groups of fish,while the protein-to-energy(P/E) ratios of the diets varied in the range of 19.74–28.32 mg k J^(-1).Results showed that fish fed diets containing 9% or 13% lipids with 54% protein exhibited significantly higher weight gains and specific growth rates than those fed other diets.The feed conversion rate of fish fed the diet with 40% protein and 5% lipids was significantly poorer than that of fish fed other diets.The protein efficiency rate of fish fed diets with 5% lipids was significantly lower than that of fish fed 9% or 13% lipid diets.Carcass lipid and energy contents were positively correlated with dietary lipid level regardless of protein level.Fish fed a 54% protein diet showed the highest trypsin activity.The intestinal lipase activity of fish fed the diet containing 13% lipids was significantly higher than that of fish fed 5% or 9% lipid diets.These results demonstrate the high protein dietary requirements of N.albiflora.A diet containing 54% protein and 9%–13% lipids with a P/E ratio of 26.2–27.81 mg protein k J^(-1) can be considered optimal for juvenile N.albiflora.

Effects of Dietary Soy Protein Concentrate on Growth, Digestive Enzymes Activities and Target of Rapamycin Signaling Pathway Regulation in Juvenile Soft-Shelled Turtle, <i>Pelodiscus sinensis</i>

Soft-shelled turtle, Pelodiscus sinensis is important aquatic species in China, and searching for alternatives protein resources to fish meal (FM)-based feeds in feed has become urgent and important for its sustainability development. The present study was conducted to assess the effects of dietary soy protein concentrate (SPC) on growth, digestive enzymes and target of rapamycin (TOR) signaling pathway of juvenile P. sinensis (4.56 ± 0.09 g). SPC was applied to replace FM protein at 0%, 15%, 30% and 60% (designated as T0, T15, T30 and T60, respectively), and each diet was fed to triplicate groups. The results showed that there was no significant difference in growth performance and feed utilization except of the turtles fed with T60 diet, of which showed poorer daily weight gain and feed conversion rate. The pepsin/trypsin and Na+-K+ ATP-ase activities decreased dramatically when SPC level increased, and lipase activities in liver and intestinal tract also showed decline tendency. However, amylase activities were unaffected. No significant differences were observed in TOR, S6K1 and 4E-BP1 genes mRNA expression level of TOR signaling pathway among the treatments. However, the relative phosphorylated level of these proteins decreased significantly when SPC level increased. The present study indicated that high SPC substitution level would suppress digestive enzymes and TOR signaling pathway proteins phosphorylated level and eventually result in growth reduction of P. sinensis.

Effects of Multi-enzyme Preparations on Growth Performance, Apparent Total Tract Digestibility and In Vitro Digestibility for Growing Pigs

The aim of this study was to investigate the effects of enzyme supplementations on performance of growing pigs, apparent total tract digestibility （ATTD） and in vitro digestibility （IVD） of nutrients. 224 growing pigs weighing 30-4-1.2 kg were allocated to fed basal diets supplemented with 0, 0.1, 0.15 or 0.2 g/kg enzyme preparations in growth trail. Those four diets were used for in vio＇o digestibility study. Pigs fed enzyme-supplemented diets improved average daily gain and decreased ratio of feed/gain （P〈0.05）. Enzyme supplementations increased ATTD of dry matter, energy, crude protein, neutral detergent fiber, acid detergent fibre and hemicellulose （P〈0.05）. Supplementation with enzymes improved reducing sugar production and the IVD of dry matter, crude protein, neutral detergent fiber, acid detergent fibre, total arabinoxylans, galacturonic acid, hemicellulose and cellulose. 0.015% enzyme supplementation in diets seemed to be sufficient to achieve maximum growth performance, nutrients digestibilities and reducing sugar production. Collectively, these results suggested that the supplementation of enzymes in diet increased the digestibilities of nutrients through the promotion of NSP degradation, thereby enhancing growth performance of growing pigs.

Effects of dietary supplementation of Lactobacillus plantarum and Bacillus subtilis on growth performance,survival,immune response,antioxidant capacity and digestive enzyme activity in olive flounder(Paralichthys olivaceus)

In present study,a 10-month feeding trial was carried out to investigate effects of dietary Lactobacillus plantarum and Bacillus subtilis supplementation singly on growth performance,innate immune response,antioxidant capacity and digestive enzyme activity of olive flounder under a commercial production environment.Two experimental groups fed basal diet with supplementation of L.plantarum(5.0×107 CFU/g diet)and B.subtilis(1.0×108 CFU/g diet)respectively,and control group fed with basal diet without probiotics supplement.At harvest,serum immune parameters,liver antioxidant indices and digestive enzyme activities in liver,stomach and intestines were measured.Fish fed with B.subtilis supplemented diet showed the highest growth rate which was significantly higher than L.plantarum supplemented group(P<0.05)which was also significantly higher than control group(P<0.05).Survival rate were significantly elevated by feeding diet with L.plantarum supplementation(P<0.05),while the improvement was not significant for B.subtilis supplemented diet compared to control group.All the studied immune parameters in serum were substantially enhanced in both experimental groups.Similar results were observed for the antioxidant capacity in liver.Besides,the activities of digestive enzymes increased substantially in both experimental groups compared to control group and the detected improvement in dietary B.subtilis supplemented group were all higher than in L.plantarum supplemented group,though not all the improvements were significant.In summary,the separate supplementation of B.subtilis and L.plantarum in diet is more beneficial for growth performance and healthy status respectively.Hence,in olive flounder aquaculture,favorable effects of compounded supplementation of L.plantarum and B.subtilis are expected.

Effects of Starving and Re-feeding Strategies on the Growth Performance and Physiological Characteristics of the Juvenile Tongue Sole(Cynoglossus semilaevis)

Starving and re-feeding trials were conducted to evaluate the effects of starvation duration and recovery times on the growth performance and physiological characteristics of juvenile tongue sole Cynoglossus semilaevis, which included growth, body composition, intestinal morphology and digestive enzymes activities. The fish starved for one(D1), two(D2) and four(D4) days, respectively, were recovered for three(R3, R6, R12), seven(R7, R14, R28) and eleven(R11, R22, R44) folds of starvation days while the control fish were fed constantly. The experiment was conducted for 96 days. The fish individuals in D1R11, D2R14 and D2R22 caught up in weight with the control, indicating that complete compensatory growth existed in these fish individuals. The highest body weight gain and total specific growth rates were observed in D2R22. Food intake increased significantly in most treatments in comparison with that of the control except for D1R7 and D2R22(P < 0.05). Food conversion efficiency and apparent digest coefficient in D2R22 were significantly promoted, being higher than that of the control(P < 0.05). The activities of trypsin and lipase were found to be closely related to the growth performance. The activities of liver and hindgut trypsin, also midgut and hindgut lipase in D2R22 were significantly higher than those of the control(P < 0.05). The fold height(HF) of foregut and midgut increased significantly in D2R22, and HF decreased significantly in D1R3, D2R6 and D4R12(P < 0.05). On our findings, we may conclude that the optimum starving and re-feeding strategy is starving for 2 days and re-feeding for 22 days. And in this starving and re-feeding strategy, the compensatory growth could be mostly attributed to the promotion of food conversion efficiency and digestibility coefficiency.

Growth performance,digestive enzyme activities and serum nonspecific immunity of the red tilapia(Oreochromis mossambicus×Oreochromis niloticus)feddiets supplemented with ultrafine powder of Enteromopha prolifera

The present study evaluated ef fects of ultrafine powder of the green macroalgae E nteromopha prolifera as dietary supplement on growth performance, digestive enzyme activities and serum nonspecific immune responses of the red tilapia(O reochromis mossambicus × Oreochromis niloticus). The red tilapia were fed five diets supplemented with different levels of E. prolifera ultrafine powder as well as a control diet containing no E. prolifera for seven weeks(Diets 0–6 contained 0(control), 10, 20, 30, 40 and 50 g/kg of E. prolifera ultrafine powder, respectively). The results showed that diets supplemented with E. prolifera ultrafine powder generally improved growth, immunity and digestive enzyme activities of the red tilapia. In particular, the fish fed the diet incorporated 50 g/kg (5%) E. prolifera ultrafine powder(Diet 5) achieved the highest percentage weight gain, specific growth rate and the condition factor(increased by 15.4%, 8.0% and 5.7%, respectively when compared to the control). Feeding the diet also led to significantly increases( P <0.05) in serum nonspecific immune responses, including total superoxide dismutase, acid phosphatase, alkaline phosphatase, lysozyme activities and serum total protein(increased by 19.4%, 48.1%, 29.5%, 30.3% and 8.7%, respectively) as well as digestive enzyme activities of erepsin, gastric amylase, gastric lipase, pepsin, intestinal amylase and gastric lipase(increased by 15.7%, 33.3%, 16.3%, 21.3%, 52.3% and 28.2%, respectively) than those of the control. Based on these results, it is recommended that the inclusion level of E. prolifera ultrafine powder in the diet of the red tilapia should be 50 g/kg(or 5%).

Effects of exogenous enzymes and dietary energy on performance and digestive physiology of broilers

The study was conducted to compare the effects of XG with AG and BM at different metabolizable energy diets on growth performance, digestive physiology and energy utilization of broilers fed with corn-SBM diet. A 2 x 4 factoria design was used with two basal diets （the positive control group, PC; negative control with ME reduction 100 kcal/ kg, NC） and with or without the addition of three exogenous enzymes （0.02% BM; 0.01% AG; 0.05% XG） respectively. 1,200 one-day-old broilers were randomly allocated to 8 treatments with 10 pens of 1_5 broilers. There was no significant difference on BW, BWG, and FI at 0-21d, 21-42d or 0-42d for diet, enzymes or their interactions, but FI at 22-42d and 0-42d were tend to be decreased with the addition of enzymes. The F/G was significantly improved by the addition of enzymes especially in NC diet. The dietary AME and TME in PC or NC diet were significantly increased by XG or AG in NC diet. The villus length and V/C of ileum were significantly increased by the addition of BM or XG. XG improved the activities of trypsin, chymotrypsin and amylase, BM improved the activity of trypsin at 21d, and AG improved the activity of chymotrypsin at 21d. Comparing to PC diet, the addition of enzymes in PC or NC diet decreased feed cost per kg body weight gain especially in NC diet （except AG in PC diet） with the highest profits for XG in NC diet. In conclusion, supplementation of 0.02% BM or 0.01% AG or 0.0.5% XG could improve feed conversion of broilers in corn-soybean meal diet by improving energy utilization and digestive physiology, and also supplementation of 0.05% XG had a preferable efficacy in low energy diet.

Effect of replacing antibiotics using multi-enzyme preparations on production performance and antioxidant activity in piglets

The study was conducted to investigate the effects of replacing antibiotics using multi-enzyme preparations on growth performance,coefficient of total tract apparent digestibility,digestive enzyme activity,and antioxidant property in piglets.A total of 160 piglets（（21.35±0.22）kg）were randomly assigned to five dietary treatments：1）basal diet supplemented with antibiotics（AC）,2）antibiotic diet supplemented with 0.5 g kg^-1 multi-enzyme preparations（AC＋0.5EP）,3）antibiotic diet supplemented with 1.5 g kg^-1 multi-enzyme preparations（AC＋1.5EP）,4）basal diet supplemented with a half dosage of antibiotics and 1.5 g kg^-1 multi-enzyme preparations（AH＋1.5EP）,and 5）basal diet supplemented with 1.5 g kg^-1 multienzyme preparations（BC＋1.5EP）.The results showed that AC＋1.5EP significantly improved the feed efficiency,apparent digestibility of ether extract（EE）and crude ash（CA）,lipase activity in pancreas and duodenum content,maltase and lactase activity in jejunum and ileum mucosa,glutathione peroxidase（GSH-Px）concentration in serum and liver,and decreased malondialdehyde（MDA）concentration in serum and liver compared with piglets receiving AC（P〈0.05）.Piglets receiving BC＋1.5EP showed no significant difference in growth performance（P〉0.05）but had lower MDA concentration than piglets receiving AC（P〈0.05）.The apparent digestibility of EE and crude fiber（CF）,duodenal lipase activity,jejunum mucosa maltase,and ileum mucosa lactase activity of piglets receiving AH＋1.5EP or BC＋1.5EP were significantly improved compared with piglets receiving AC（P〈0.05）.These results indicated an additive growth promotion effect between antibiotics and multi-enzyme preparations on piglets,and the multi-enzyme preparations may be used as substitutes for antibiotics for improving piglet production performance and health status.

Effects of neutral phytase on growth performance and phosphorus utilization in crucian carp(Carassius auratus)

A feeding trial was conducted for nine weeks to investigate the effects of partially replacing Ca（H2PO4）2 with neutral phytase on the growth performance, phosphorus utilization, nutrient digestibility, serum biochemical parameters, bone and carcass mineral composition, and digestive-enzyme-specific activity in crucian carp（Carassius auratus）.The diets prepared with 0.8%, 0%, and 1.8% Ca（H2PO4）2（1%=1 g/100 g） supplements were regarded as the P1E0, negative control（NC）, and positive control（PC） groups, respectively; the other three experimental diets were prepared with the addition of 200, 300, and 500 U/kg of neutral phytase, respectively, based on the P1E0 group.Three hundred and eighty-four fish（（1.50±0.01） g） were randomly distributed in the six treatments with four replicates each.The fish were initially fed with 2%–3% diets of their body weight per day, with feeding twice daily（08：00 and 16：00）, under a 12-h light/12-h dark cycle at the temperature of（27.56±0.89） ℃.The results showed that supplemental phytase at different levels in the diet improved the final body weight, average daily gain, feed conversion ratio, phosphorus utilization, and protein efficiency ratio of crucian carp（P〈0.05）.Phytase supplementation increased the mineral content in serum（P）, bone（P, Ca）, and carcass（P, Ca, Zn, Na, and Mg）（P〈0.05）; the trypsin and chymotrypsin activity soared when fed with the phytase-supplemented diets（P〈0.05）.We may conclude that supplemental dietary neutral phytase improved the growth performance, phosphorus utilization as well as nutrient utilization in crucian carp, and it can be considered an important nutritional replacement for Ca（H2PO4）2.

Antimicrobial ability and growth promoting effects of feed supplemented with probiotic bacterium isolated from gut microflora of Cirrhinus mrigala

The present studies were conducted to isolate, select, identify and characterize gut bacteria as antimicrobial and growth promoting agent for the feed of economically important fish Cirrhinus mrigala. Intestinal microflora were isolated, counted, and identified, and their in vitro antibacterial properties were determined. The results have revealed that occurrence of Gram-negative rods was around 75% and of Gram-positive rods was 25%. Among the isolates Gram-positive were maintained in nutrient agar slants at 4℃. Of these, eight strains were replica-plated on agar seeded with Aeromonas hydrophila and only one strain CM2（C. mrigala 2） exhibited antibacterial properties in vitro showing inhibition against fish pathogen by well diffusion assay. This isolated strain was identified as Bacillus cereus. This bacterium was mass cultured and incorporated in the pelleted diet（40% protein and 18 k J g^–1 gross energy） of C. mrigala to investigate its effect on growth performance, digestibility, nutrient retention and activities of digestive enzymes. The results of feeding trial revealed significantly（P〈0.05） high growth performance in terms of specific growth rate, growth percent gain in body weight（BD）（272.4±1.5）%, high apparent protein digestibility（（79.9±0.30）%） and low food conversion ratio in the group of fishes fed on diet containing B. cereus in comparison to the fishes fed on diet without probiotics. The carcass composition also revealed high accumulation of proteins（（15.28±0.15） g 100 g^–1） in fishes fed on diet containing probiotics. Intestinal enzyme activities of protease, amylase and cellulase were also significantly（P〈0.05） high in the group of fishes fed on diet supplemented with probiotics indicating the extracellular enzyme production by B. cereus. These results indicate that probiotics stimulate the digestion through the supply of digestive enzyme and certain essential nutrients to animals. Also significantly（P〈0.05） low excretion of metabolites, i.e., ammonia excretion and phosphate production（mg kg^–1 BW d^–1） was observed in the fishes fed with probiotic based diets. Thus, B. cereus appears to be a promising candidate for ptobiotic applications which can enhance growth performance and nutrient retention in C. mrigala.

饲料蛋白和脂肪水平对太湖鲂鲌冬片鱼种生长、体组成和消化酶活性的影响

为优化太湖鲂鲌配合饲料配方,设计3个饲料蛋白水平(36%、39%和42%)和3个脂肪水平(6%、8%和10%)的3×3因子实验,配制9种实验饲料(P36L6、P36L8、P36L10、P39L6、P39L8、P39L10、P42L6、P42L8和P42L10),分别饲喂9组3重复平均体重为8.59 g的太湖鲂鲌冬片鱼种60d,以探讨饲料中不同含量的蛋白和脂肪对太湖鲂鲌冬片鱼种生长、饲料利用、体成分和肠道消化酶等的影响。结果表明:实验鱼摄食蛋白水平为39%和42%的6种饲料(P39L6、P39L8、P39L10、P42L6、P42L8和P42L10)后,其鱼体增重率和饲料系数在组间无显著差异(P>0.05),但鱼体增重率均比摄饲料蛋白水平为36%的3种饲料(P36L6、P36L8和P36L10)的实验组要高(P<0.05),而饲料系数则较低;在同一饲料蛋白水平时,饲料脂肪水平变化对蛋白质沉积率无显著影响;摄食蛋白质水平为39%饲料的3个实验组的蛋白质沉积率均高于饲料蛋白为36%的3个实验组。饲料同一脂肪水平时,饲料蛋白水平从39%提高到42%对蛋白质沉积率有降低的趋势,但差异不显著;脏体指数(VSI)与饲料脂肪水平(L)呈正相关(VSI=0.223L+4.611,R=0.746,P=0.000);全鱼粗脂肪随饲料蛋白的升高而降低,但随饲料脂肪水平的升高而增加;摄食3种低脂肪水平(6%)的饲料(P36L6、P39L6和P42L6)的太湖鲂鲌肌肉粗脂肪含量均显著低于摄食其他6种脂肪水平较高(8%和10%)饲料组;摄食3种蛋白水平为36%的饲料(P36L6、P36L8和P36L10)后,太湖鲂鲌肠道淀粉酶活性显著高于蛋白水平39%和42%的饲料组;太湖鲂鲌肠道蛋白酶和脂肪酶活性均不受饲料蛋白和脂肪水平及其交互作用的影响;因此,能使实验鱼获得良好生长和饲料利用的适宜饲料蛋白和脂肪水平分别为39%和6%。过低的饲料蛋白水平和过高的饲料脂肪水平易导致鱼体脂肪积累过多。

低鱼粉饲料添加复合益生菌对小龙虾生长性能、消化酶活性及肉品质的影响

文章旨在研究低鱼粉饲料添加复合益生菌对小龙虾生长性能、消化酶活性及肉品质的影响。试验于XX小龙虾养殖场进行,选择均重(3.48±0.34)g体态好、附足完整且齐全、活力强的小龙虾600尾,随机分为4组,每组5个重复,对照组饲喂基础日粮,试验组日粮在对照组基础上降低2%鱼粉并分别添加0、150和300 mg/kg的复合益生菌。结果表明,与对照组相比,试验Ⅰ和Ⅱ组小龙虾末重分别显著降低9.29%和10.5%(P <0.05);同时,试验Ⅲ组与对照组小龙虾末重无显著差异(P> 0.05);试验Ⅰ和Ⅱ组小龙虾特定生长率分别显著降低3.69%和4.18%(P <0.05);同时,试验Ⅲ组与对照组小龙虾特定生长率无显著差异(P <0.05);试验Ⅰ~Ⅲ组出肉率较对照组分别显著降低7.07%、5.53%和3.92%(P <0.05)。试验Ⅰ~Ⅲ组小龙虾肝胰腺的胰蛋白酶活性较对照组显著提高(P <0.05);对照组和试验Ⅲ组小龙虾肝胰腺的纤维素酶活性显著高于其他两组(P <0.05);试验Ⅰ~Ⅲ组小龙虾肠道淀粉酶活性较对照组显著提高(P <0.05);试验Ⅱ和Ⅲ组小龙虾肠道纤维素酶活性较其他两组显著提高(P <0.05)。试验Ⅰ~Ⅲ组小龙虾肉硬度和胶黏性较对照组显著降低(P <0.05);对照组和试验Ⅲ组小龙虾肉的咀嚼性较其他两组显著提高(P <0.05)。结论 :降低2%的鱼粉并添加复合益生菌对小龙虾消化酶活有一定的提高作用,但对小龙虾生长和肉质有显著负面影响。

投喂不同饵料对斑鳜生长及消化性能的影响

【目的】探明斑鳜(Siniperca scherzeri)摄食配合饲料后其生长与消化性能的变化规律,为开展以配合饲料替代传统饵料鱼的斑鳜规模养殖提供参考依据。【方法】选取驯化和未驯化斑鳜苗种各180尾,分别投喂配合饲料和活饵鱼,饲养20周后饥饿24 h,测定分析其生长性能、消化酶活性、肠道组织结构及肠道微生物群落结构。【结果】至饲养20周后,饲料组斑鳜的存活率、脏体比与活饵组斑鳜相比无显著差异(P>0.05,下同),但终末体质量、增重率及饲料系数显著低于活饵组斑鳜(P<0.05,下同);饲料组斑鳜肠道α-淀粉酶活性显著高于活饵组斑鳜,胰蛋白酶活性显著低于活饵组斑鳜,而胃蛋白酶和脂肪酶活性无显著差异。此外,饲料组斑鳜肠道的肌层厚度和黏膜褶皱高度均显著低于活饵组斑鳜,但二者间的肠黏膜褶皱数无显著差异。在肠道微生物群落方面,饲料组斑鳜肠道微生物群落的ACE指数和Chao1指数显著低于活饵组斑鳜,但Shannon指数和Simpson指数无显著差异;2种饵料投喂模式下斑鳜肠道微生物群落结构均以变形菌门、厚壁菌门、软壁菌门和放线菌门为绝对优势菌门,其相对丰度之和在98.00%以上;在属分类水平上,饲料组斑鳜肠道内的伯克霍尔德菌属相对丰度显著高于活饵组斑鳜,而鞘氨醇盒菌属和支原体属相对丰度显著低于活饵组斑鳜。【结论】以配合饲料替代活饵投喂斑鳜,其生长速度显著降低,肠道组织结构、消化酶活性及肠道微生物群落结构出现适应性变化,尤其是配合饲料的投喂有助于维持肠道微生物稳定性。可见,以配合饲料替代活饵养殖斑鳜具有可行性,但还需进一步优化饲料营养组分及投喂策略,提高配合饲料养殖下斑鳜的生长速率。

饲粮中添加菌酶制剂对犊牛生长性能、肠道菌群及养分表观消化率的影响

试验旨在研究不同水平的菌酶制剂对犊牛生长性能、肠道菌群及养分表观消化率的影响。选择36头体重相近的荷斯坦犊牛,随机分成4组,每组9个重复,每个重复1头犊牛。对照组饲喂基础饲粮,试验组分别饲喂添加0.1%、0.2%和0.4%的菌酶制剂饲粮。试验期30 d。结果表明:与对照组相比,0.2%和0.4%菌酶制剂组的末重和平均日增重显著提高(P<0.05),料重比显著降低(P<0.05),所有菌酶制剂组犊牛的腹泻率均显著降低(P<0.05);所有菌酶制剂组犊牛肠道中的乳酸菌数量显著提高(P<0.05),大肠杆菌数量和沙门氏菌数量显著降低(P<0.05);0.2%和0.4%菌酶制剂组犊牛肠道中好氧菌总数显著降低(P<0.05);0.2%和0.4%菌酶制剂组犊牛的有机物、干物质的表观消化率显著升高(P<0.05),所有菌酶制剂组犊牛的粗蛋白、中性洗涤纤维和酸性洗涤纤维的表观消化率显著升高(P<0.05)。研究表明,添加适量的菌酶制剂可以改善犊牛的肠道菌群结构及机体对饲粮中营养物质的消化吸收,进而提高生长性能,菌酶制剂的适宜添加量为0.2%。

酵母水解物对克氏原螯虾生长性能、消化、抗氧化和免疫能力的影响

实验研究了添加不同水平酵母水解物(Yeast hydrolysate,YHY)对克氏原螯虾(Procambarus clarkii)生长性能、消化、抗氧化和非特异性免疫能力的影响。实验选用300尾平均体重为(6.43±0.55)g的个体,随机分为5组,分别饲喂在基础饲料中添加0(对照组)、0.5%、1%、2%和4%YHY的饲料,每组3个重复,养殖密度为20尾/缸。为期8周的实验结束后,测定克氏原螯虾生长指标、胃和肝胰腺消化酶活性、肝胰腺抗氧化性能、血清生化指标和免疫酶活性。结果表明:(1)饲料中添加1%—4%YHY对该虾生长指标有促进作用。其中,2%添加组的存活率(SR)、最终体重(FBW)、最终体长(FBL)和肝胰腺指数(HSI)达最大值且显著高于对照组(P<0.05),增重率(WGR)和特定生长率(SGR)在1%添加组达到最大值且显著高于其余各组(P<0.05);(2)1%YHY添加组的全虾粗蛋白质含量显著高于其他组(P<0.05),而肌肉粗蛋白和粗脂肪含量在2%添加组达到最大值;(3)与对照组相比,2%—4%YHY添加组的胃和肝胰脏消化酶活性显著提高(P<0.05);(4)2%YHY添加组的肝胰腺抗氧化酶(过氧化氢酶,CAT;总超氧化物歧化酶,T-SOD;总抗氧化能力,T-AOC)和免疫酶(碱性磷酸酶,AKP;酸性磷酸酶,ACP)的活性达到最大值、丙二醛(MDA)的含量达到最小值,且与对照组相比均有显著差异(P<0.05);(5)2%YHY添加组该虾血清中总蛋白(TP)和白蛋白(ALB)含量显著高于其他组(P<0.05),1%和2%YHY添加组谷丙转氨酶(ALT)和谷草转氨酶(AST)活性显著低于其他各组(P<0.05)。结果表明,饲料中添加2%的酵母水解物可显著提高克氏原螯虾的消化、生长及肌肉粗蛋白和粗脂肪含量,并显著改善其抗氧化和非特异性免疫能力。

低蛋白日粮添加复合酶对生长猪生长性能、养分利用率及有害气体排放的影响

文章旨在探究低蛋白日粮添加复合酶对生长猪生长性能、养分利用率及有害气体排放的影响。试验将120头平均体重为(48.59±1.27)kg的90日龄杂交生长猪随机分为4组,每组5个重复,每个重复6头。试验为期101 d(其中预饲期8 d,正试期93 d)。试验日粮分别向低蛋白饲粮中添加0、300、600和900 mg/kg的复合酶制剂。结果表明,较对照组,日粮添加600和900 mg/kg复合酶可显著提高生长猪4.8%和6.7%的终末体重(P <0.05);显著提高生长猪8.5%和12.4%的平均日增重;显著提高生长猪3.4%和7.7%的平均日采食量(P <0.05);显著降低生长猪4.8%和6.4%的料重比(P <0.05)。较对照组,日粮添加600和900 mg/kg复合酶显著提高生长猪粗蛋白、氮和能量的表观消化率(P <0.05)。较对照组,日粮添加600和900 mg/kg复合酶显著降低生长猪的粪氮和粪磷排放(P <0.05);日粮添加600和900 mg/kg复合酶显著降低生长猪4~24 h氨气排放;此外,本试验未检测到硫化氢的排放。总之,本试验条件下,复合酶最适添加量为900 mg/kg。

桑叶低聚糖对大口黑鲈生长性能以及肠道消化酶活性、免疫功能和菌群的影响

本试验旨在探究饲料中添加桑叶低聚糖(MLO)对大口黑鲈生长性能以及肠道消化酶活性、免疫功能和菌群的影响。试验选择平均初始体重为(26.89±1.16)g的大口黑鲈幼鱼450尾,随机分成3组,每组3个重复,每个重复50尾。对照组饲喂基础饲料,试验组分别饲喂在基础饲料的基础上添加0.5%和1.0%MLO的试验饲料。试验期80 d。结果表明:1)与对照组相比,试验组大口黑鲈饲料系数(FCR)和脏体比(VSI)显著降低(P<0.05),1.0%MLO组肝体比(HSI)显著降低(P<0.05)。2)与对照组相比,试验组大口黑鲈肠道α-淀粉酶、脂肪酶和胰蛋白酶活性显著提高(P<0.05),试验组肠道绒毛高度、绒毛宽度和肌层厚度均无显著差异(P>0.05)。3)与对照组相比,试验组大口黑鲈肠道菌群Sobs指数、ACE指数和Chao1指数显著降低(P<0.05);0.5%MLO组Simpson指数显著高于对照组和1.0%MLO组(P<0.05)。在门水平上,与对照组相比,试验组大口黑鲈肠道厚壁菌门(Firmicutes)相对丰度显著降低(P<0.05),肠道变形菌门(Proteobacteria)、梭杆菌门(Fusobacteriota)和拟杆菌门(Bacteroidota)相对丰度显著提高(P<0.05),厚壁菌门/拟杆菌门值显著提高(P<0.05)。在属水平上,与对照组相比,试验组肠道支原体属(Mycoplasma)相对丰度显著降低(P<0.05),肠道不动杆菌属(Acinetobacter)、乳杆菌属(Lactobacillus)和芽孢杆菌属(Bacillus)相对丰度显著提高(P<0.05)。4)与对照组相比,试验组大口黑鲈肠道白细胞介素-8(IL⁃8)、核因子-κB(NF⁃κB)和肿瘤坏死因子-α(TNF⁃α)mRNA相对表达量显著降低(P<0.05),肠道白细胞介素-10(IL⁃10)和转化生长因子-β(TGF⁃β)mRNA相对表达量显著提高(P<0.05)。综上所述,饲料中添加MLO能够降低大口黑鲈FCR、VSI和HSI,提高肠道消化酶活性,并调节肠道菌群,改善肠道益生菌相对丰度,增强其免疫功能。

复方中草药对兔生长性能和肠道健康的影响

为了研究复方中草药对兔生长性能、免疫功能、肠道消化酶活性、抗氧化能力、肠道形态和肠道微生物的影响,本试验选取72只5周龄健康新西兰大白兔,随机分成对照组(CN,饲喂基础饲粮)和中草药组(CM,基础饲粮中添加600 mg/kg复方中草药),每组36只,试验周期为42 d。每周测定各组兔的采食量和体增重,计算平均日采食量(ADFI)、平均日增重(ADG)和料重比(F/G);试验第21、42天,每组随机选择4只健康兔,采血分离血清,检测生化指标和免疫指标;试验结束(第42天),收集兔小肠肠段,通过ELISA检测小肠黏膜消化酶活性和抗氧化指标,苏木精-伊红(H.E.)染色观察小肠绒毛形态,实时荧光定量PCR(qRT-PCR)检测紧密连接蛋白mRNA的相对表达量,高通量测序分析盲肠微生物多样性。结果显示,两组间ADFI、ADG和F/G均差异不显著(P>0.05)。与对照组相比,在试验第21天时,中草药组兔血清中总胆固醇(Tchol)含量极显著降低(P<0.01);在试验第42天时,中草药组兔血清中免疫球蛋白M(IgM)含量和回肠黏膜中分泌型免疫球蛋白A(sIgA)含量显著升高(P<0.05);肠道中消化酶(α-淀粉酶、糜蛋白酶和胰蛋白酶)活性显著升高(P<0.05);空肠中超氧化物歧化酶(SOD)活性显著升高(P<0.05),谷胱甘肽过氧化物酶(GSH-Px)活性显著降低(P<0.05),十二指肠和空肠中丙二醛(MDA)含量显著降低(P<0.05);空肠绒毛长度(V)显著增长(P<0.05),隐窝深度(C)显著降低(P<0.05),绒毛长度与隐窝深度比值(V/C)极显著升高(P<0.01);十二指肠中闭锁蛋白(Occludin)mRNA相对表达量显著上调(P<0.05),回肠中膜周蛋白(ZO-1)和Occludin mRNA相对表达量也显著上调(P<0.05);盲肠内容物细菌16S rRNA基因的菌群丰富度指数(Chaol)丰度值显著升高(P<0.05);盲肠在属水平分类上的主要优势菌群为梭菌属(Clostridiales)和阿克曼菌属(Akkermansia)等。结果表明,兔日粮中添加中草药饲料添加剂能增强机体免疫力和抗氧化能力,维持肠道黏膜形态的完整,提高肠道消化酶活性,改善肠道菌群。