Dietary supplementation of laminarin improves the reproductive performance of sows and the growth of suckling piglets

Background Maternal nutrition is essential in keeping a highly efficient production system in the pig industry.Laminarin has been shown to improve antioxidant capacity,reduce the inflammatory response,and favor the homeostasis of intestinal microbiota.However,the effect of dietary supplementation of laminarin on the reproductive performance of sows and the growth of suckling offspring remains unknown.Methods A total of 40 Landrace×Yorkshire multiparous sows on d 85 of gestation,similar in age,body weight(BW),parity and reproductive performance,were randomly divided into four dietary treatments with 10 sows per treatment,receiving a control diet(basal pregnancy or lactating diets)and a basal diet supplemented with 0.025%,0.05%and 0.10%laminarin,respectively.The experiment lasted from d 85 of gestation to d 21 of lactation.Results Laminarin supplementation linearly increased number born alive per litter(P=0.03),average daily feed intake(ADFI,P<0.01),and total milk yield of sows during the lactation of 1–21 d(P=0.02).Furthermore,maternal laminarin supplementation increased the average daily gain(ADG)of piglets while tending to reduce the culling and death rate before weaning.In addition,alterations to the composition of colostrum and milk,as well as to serum inflammatory cytokines and immunoglobulins of sows were observed.The fecal microbiota profile of sows supported the improvement of reproductive performance in sows and the growth performance in suckling offspring.Conclusions Dietary supplementation of laminarin during late pregnancy and lactation could significantly improve reproductive performance of sows and growth performance of piglets.

Study on Breeding Practices and Reproductive Performance of Black-Head Somali Sheep under Traditional Management System: The Case of Awbarre District, Eastern Ethiopia

The study was conducted in the Awbarre district of the Fafen zone of the Somali regional state of Ethiopia. The objective of the study was to assess the breeding practices and reproductive performance of Black-head Somali sheep under a traditional management system. Purposive and simple random sampling techniques were used to select targeted kebeles and households, respectively. A total of 120 households were selected from four kebeles, each of 30 households, based on the production system and sheep population. Semi-structured questionnaires, group discussions, key informants interviews and field observations were used to generate the required data. The primary purpose of keeping sheep was for income generation, followed by saving as a future asset. The majority (89.2%) of the respondents separated male and female animals during herding. The selection criteria for breeding rams were appearance, growth, pedigree, and color while for breeding ewes were appearance, adaptability, pedigree, color, and lamb growth. The overall weaning age of Black-head Somali sheep in the study area was 3.7 months for both males & females. The castration of male sheep was common for the purpose of fattening, fattening with breeding control and breeding control as well. The castration is mainly performed during the summer and autumn and the methods of castration were both traditional and modern methods, the traditional castration method being the most important one in pastoral areas. The age of sexual maturity was 7.64 months for rams and 8.97 months for ewe’s male and female lambs in the pastoral area and 8.42 & 8.38 for rams & ewes in agro-pastoral and overall lambing interval was 11 months. On average, the ewe of Black-head Somali sheep in pastoral & agro-pastoral could produce 9.49 & 9.57 lambs, respectively in their lifetime. As the pastoralists and agro-pastoralists indicated the source of the breeding ram was their own, so the exchange of breeding ram is recommended to minimize the risk of inbreeding and further studies of on-farm performance investigation would be necessary to be carried out so as to understand the uniqueness of the breed better.

Effects of melatonin implantation on cashmere yield,fibre characteristics,duration of cashmere growth as well as growth and reproductive performance of Inner Mongolian cashmere goats

Background： Exogenous melatonin could induce cashmere growth. However, induced growth of cashmere fleece by melatonin implants cannot be combined with the typical growth, resulting in earlier shedding followed by another cycle of cashmere growth. To address this issue, we examine the effects on the cashmere yield, fibre characteristics, and the growth and reproductive performance of cashmere goats of planned administration of melatonin. Methods： Eighteen half-sib, female goats were assigned to two treatments （n = 9） including a control and a treatment where melatonin （2 mg/kg BW） was implanted at the end of April and end of June. Cashmere growth and shedding were observed for approximately ] year following implantation. Fibre samples were collected monthly to determine cumulative cashmere length. Initiation and cessation dates for cashmere growth as well as the rate of cashmere growth were calculated. Cashmere yield, weight gain of dam, kidding date, litter size, and birth weight were also recorded. Results： Melatonin implantation increased cashmere yield by 34.5 % （control 553.7 g vs. melatonin 745.0 g; P〈 0.01）, cashmere length by 21.3 % （control 95.2 mm vs. melatonin 115.4 mm; P 〈 0.01）, and decreased fibre diameter by 4.4 % （control 14.6 pm vs. melatonin 14.0 IJm; P 〈 0.03）. In melatonin-treated goats, the average initiation date was earlier than in control goats （May 18, 2013 vs. July 2, 20]3; P〈 0.01） but there was a similar cessation date （March 22, 2014 vs. March 27, 2014）. Consequently, the duration of cashmere growth was longer in melatonin-treated goats than in control goats （307 vs.270 days; P 〈 0.01）. The final BW, average daily gain, kidding date, litter size, and birth weight were not influenced by melatonin implantation. Conclusions： These data indicate that melatonin implantation （2 mg/kg BW） on two occasions （late April and June） increased cashmere yield by combining the induced growth of cashmere fleece with the typical growth and decreased the fibre diameter without changing dam growth rate or reproductive performance.

Inclusion of purified dietary fiber during gestation improved the reproductive performance of sows

Background: This study aimed to investigate the impacts of guar gum and cellulose as the source of dietary fiber during gestation on the reproductive performance of sows.Methods: A total of 210 sows(parities 3–6) were randomly allocated into six diets(n = 35) throughout gestation to feed graded levels of dietary fiber(DF), including a corn-soybean meal-based control diet with no wheat bran inclusion(CON, 12.5% DF), a wheat bran-rich diet(DF1, 17.4% DF), and another 4 diets(DF2, 17.7% DF;DF3, 18.1%DF;DF4, 18.4% DF;DF5, 18.8% DF) in which wheat bran were equally substituted by 1%, 2%, 3% and 4% purified FIBER MIX(guar gum and cellulose, 1:4). All sows received similar DE and other nutrients throughout gestation.Results: DF treatment during gestation resulted in normal fecal score(1 to 5 with 1 = dry and 5 = watery) in sows compared with those received the CON diet(P < 0.05). The number of total born piglets had a tendency to be affected by dietary treatment(P = 0.07), and correlation analysis revealed a linear response of total born to dietary fiber levels during gestation(P < 0.01). Sows received the DF2, DF3, and DF5 diets during gestation had a greater ADFI during lactation compared with those in the CON group(P < 0.05) without affecting the daily body weight gain of suckling piglets. Gut microbiota compositions were dramatically changed by the gestation stage and some of those were changed by DF inclusion. Fecal acetate, propionate, and butyrate of sows were markedly increased in late gestation, and butyrate contents in feces of gestating sows were significantly affected by DF levels(P < 0.01).Serum concentrations of pro-inflammatory TNF-α were decreased and anti-inflammatory IL-10 was increased on day30 of gestation by DF levels(P < 0.05).Conclusions: In summary, increasing dietary fiber levels by guar gum and cellulose during gestation improved the reproductive performance of sows, which might be related to changes in immunity and gut microbiota of sows.

A systematic review and meta-analysis of dietary fat effects on reproductive performance of sows and growth performance of piglets

Effects of added fat in sow diets on the sows’reproductive performance and offspring growth performance are influenced by multiple factors such as genetics,nutrition,parity,ambient temperatures,and farm management.Individual studies cannot cover all these factors.With the view to address this challenge,we searched all studies that were published from 1986 to 2020,and performed a systematic review and meta-analysis on the fat effect.In total,19 papers were collected and analyzed.Fat supplementation in sow diets during late gestation and lactation decreased average daily feed intake(ADFI,P<0.05)and tended to increase average daily energy intake(ADEI,P=0.11).It had no impact on litter weights at birth(P=0.40)or weaning(P=0.46).It increased total numbers of piglets at birth(P=0.07),but had no effect on liveborn per litter(P=0.90)or survival rate(P=0.48)of piglets to weaning.Fat supplementation had no significant effect on sow body weight loss(P=0.67)or backfat thickness changes(P=0.66),but sows fed diets with added fat had increased milk fat concentration(P=0.03)and shorter wean to estrus intervals(WEI,P=0.01).In specific circumstances,fat supplementation tended to improve growth performance of piglets with low litter weights at birth(P=0.14),or when the sows lost large amounts of body weight during lactation(P=0.11).The level of supplemented fat was 10%and higher would decrease liveborn per litter at neutral temperature(P=0.10).The meta-analysis revealed that fat supplementation to sows diet during late gestation and lactation can be beneficial for sow reproductive performance and litter growth performance.

Zearalenone toxicosis on reproduction as estrogen receptor selective modulator and alleviation of zearalenone biodegradative agent in pregnant sows

Background:Zearalenone(ZEA)is a resorcylic acid lactone derivative derived from various Fusarium species that are widely found in food and feeds.The molecular structure of ZEA resembles that of the mammalian hormone 17β-oestradiol,thus zearalenone and its metabolites are known to compete with endogenous hormones for estrogen receptors binding sites and to activate transcription of oestrogen-responsive genes.However,the effect of long-term low-dose ZEA exposure on the reproductive response to Bacillus subtilis ANSB01G culture for first-parity gilts has not yet been investigated.This study was conducted to investigate the toxic effects of ZEA as an estrogen receptor selective modulator and the alleviating effects of Bacillus subtilis ANSB01G cultures as ZEA biodegraders in pregnant sows during their first parity.Results:A total of 80 first-parity gilts(Yorkshire×Landrace)were randomly assigned to four dietary treatments during gestation:CO(positive control);MO(negative control,246μg ZEA/kg diet);COA(CO+B.subtilis ANSB01G culture with 2×10^(9)CFU/kg diet);MOA(MO+B.subtilis ANSB01G culture with 2×10^(9)CFU/kg diet).There were 20 replications per treatment with one gilt per replicate.Feeding low-dose ZEA naturally contaminated diets disordered most of reproductive hormones secretion and affected estrogen receptor-αand estrogen receptor-βconcentrations in serum and specific organs and led to moderate histopathological changes of gilts,but did not cause significant detrimental effects on reproductive performance.The addition of Bacillus subtilis ANSB01G culture to the diet can effectively relieve the competence of ZEA to estrogen receptor and the disturbance of reproductive hormones secretion,and then ameliorate toxicosis of ZEA in gilts.Conclusions:Collectively,our study investigated the effects of feeding low-dose ZEA on reproduction in pregnant sows during their first parity.Feeding low-dose ZEA could modulate estrogen receptor-αand-βconcentrations in specific organs,cause disturbance of reproductive hormones and vulva swelling,and damage organ histopathology and up-regulate apoptosis in sow models.Diet with Bacillus subtilis ANSB01G alleviated negative effects of the ZEA on gilts to some extent.

Effects of Different Dietary Crude Protein Levels on Reproductive Performance in Breeder Roosters

[Objective] To investigate effects of different dietary crude protein levels on reproductive performance and find out the optimal additive proportion of crude protein. [Method] A total of 45 New Yangzhou breeder roosters at 21 weeks old were sampled and divided into three groups, namely, low-protein diet group, medium-protein diet group and high-protein diet group. They were fed with diets respectively at crude protein levels of 17.23%, 13.04% and 11.32%. The sperm volume, testicular traits and levels of reproductive hormones were analyzed during the whole repro- ductive period. [Result] The sperm volume, sperm motility and sperm density of the medium-protein diet group were higher than that of the other two groups, and the sperm deformity rate of the medium-protein diet group was lowest. The rooster＇s testicular traits including weight, volume and testis indexes were not significantly affected by different protein levels, but the testis shrank slowly with aging （ P 〈 0.05）. The levels of testosterone （T）, luteinizing hormone （LH） and follicule stimulating hormone （FSH） in plasma were respectively 6.34%, 19.64% and 3.88% higher in the lowprotein diet group than in the medium-protein diet group, and these indexes were respectively 7.20%, 17.54% and 9.84% higher in the low-protein diet group than in the high-protein diet group. But all these differences were not significant. [ Conclusion] The breeder roosters fed with the diet at the crude protein level of 13.04% show better reproductive performance and economic efficiency.

A novel method to improve sow reproductive performance:Combination of pre-weaning immunization against inhibin and post-insemination hCG treatment

The feasibility of a novel method to improve sow reproductive performance by combining inhibin immunization and hCG treatment was tested using in vivo and in vitro experiments. In the in vivo experiment, 106 sows were administered an inhibin immunogen on day 7 prior to weaning, and 56 non-treated sows served as the controls. Sows exhibiting oestrous behaviour on day 5 after weaning were artificially inseminated. On day 5 post-insemination, a subset of 50 inhibin-immunized sows received an injection of 1000 IU human chorionic gonadotropin (hCG). Our results showed that pre-weaning immunization against inhibin marginally improved (P=0.068) total litter size and significantly increased (P=0.044) the live litter size. The overall differences in farrowing rates and live litter size tended toward significance (P=0.10) in the three groups, and the differences in total litter size were not significant (P=0.18). In the in vitro experiment, activin and hCG dose-dependently suppressed (P<0.001) and stimulated (P<0.001) progesterone (P4) secretion in cultured pig granulosa cells (GCs), respectively, and the suppression effect of activin was reversed (P<0.001) by hCG. Activin suppressed P4 secretion mainly by downregulating (P<0.001) the expression of StAR, Cyp11a1, and 3β-HSDII, whereas hCG prevented (P<0.001) the suppression effects. These results indicate that the combination of pre-weaning immunization against inhibin and postinsemination hCG treatment provides a novel method for improving sow reproductive performance.

Genetic analysis of reproductive performance in sows during porcine reproductive and respiratory syndrome(PRRS)and porcine epidemic diarrhea(PED)outbreaks

Background: Porcine reproductive and respiratory syndrome(PRRS) is one of the most infectious swine diseases in the world, resulting in over 600 million dollars of economic loss in the USA alone. More recently, the USA swine industry has been having additional major economic losses due to the spread of porcine epidemic diarrhea(PED).However, information regarding the amount of genetic variation for response to diseases in reproductive sows is still very limited. The objectives of this study were to identify periods of infection with of PRRS virus(PRRSV) and/or PED virus(PEDV), and to estimate the impact their impact on the phenotypic and genetic reproductive performance of commercial sows.Results: Disease(PRRS or PED) was significant(P < 0.05) for all traits analyzed except for total piglets born.Heritability estimates for traits during Clean(without any disease), PRRS, and PED ranged from 0.01(number of mummies;Clean and PED) to 0.41(abortion;PED). Genetic correlations between traits within disease statuses ranged from-0.99(proportion born dead with number weaned;PRRS) to 0.99(number born dead with born alive;Clean). Within trait, between disease statuses, estimates ranged from-0.17(number weaned between PRRS and PED) to 0.99(abortion between Clean and PRRS).Conclusion: Results indicate that selection for improved performance during PRRS and PED in commercial sows is possible and would not negatively impact performance in Clean environments.

Growth Development and Reproductive Performance of Congjiang Fragrance Pig

[Objective] The paper was to determine whether the germplasm resources of Congjiang fragrance pig had changed over the past 30 years. [Method]The growth development and reproductive performance of 100 pigs from six towns in central fragrance pig producing area and Congjiang fragrance pig stock seed farm were measured,and further compared with the data in Guizhou Livestock and Poultry Breeds 1986. [Result]The growth and development status was basically consistent,and the average litter size was at a downward trend: the first litter decreased by 26. 2%; the second litter decreased by 7. 0%; the third litter decreased by8. 55%. [Conclusion] The study laid the foundation for vigorous promotion of Congjiang fragrance pig in industrial development process,acceleration of breeding pace,gradual updating of farming breeds by farmers and improvement of production efficiency of fragrance pig.

Effects of Dietary Metabolizable Energy and Crude Protein Levels on Reproductive Performance of Magang Geese

[ Objective] To investigate the effects of different levels of metabolizable energy and crude protein on egg laying performance and hatch- ing efficiency in Magang geese. [Method] The healthy Magang geese at 2 years old were randomly assigned into four groups, group Ⅰ, group Ⅱ, group Ⅲ and control group. They were fed with diets at different levels of metabolizable energy and crude protein, and then their eggs were collect- ed and hatched. During the test, their health was observed, and the egg weight, egg yield and hatching rate were recorded. [ Result] The average egg laying rates and average egg weight were significantly higher in the group Ⅰ, group Ⅱ and group Ⅲ than in the control group. The hatchable egg rates and egg fertilization rates of the group Ⅰ, group Ⅱ and group Ⅲ were also increased, and significance was found between the group Ⅲ and the other group （P 〈 0.05）. The feed costs of the three test groups were lower than that of the control group, and the feed cost was higher in the group Ⅲ than that in the group Ⅰ and Ⅱ. [ Conclusion] The levels of metabolizable energy and crude protein in diet have significant effects on laying performance and hatching efficiency in Magang geese.

Research Progress on the Effects of Dietary Fiber Regulating Gut Microbiota on Sows Reproductive Performance

Dietary fiber(DF)is an essential nutrient in sow diet.It can increase sow satiety and prevent constipation.It can also regulate sow gut microbiota,and the interaction between the two can regulate sows reproductive performance and metabolic function and the growth performance of offspring piglets.It can be seen that the benefits of DF in sow production are inseparable from the interaction of gut microbiota.This paper reviewed the effects of DF on the diversity of sows gut microbiota,and the effects of DF-gut microbiota interaction on sows gut microbiota,metabolism,ovulation and lactation,as well as on offspring production performance,aiming to provide a new strategy for the application and research in sow diet.

Effect of Poly-β-hydroxybutyrate on Reproductive Performance and Larval Development of Fenneropenaeus chinensis

In the present study, Fenneropenaeus chinensis individuals were assigned into six groups, and fed with a diet supplemented with 0 （Control）, 0.5% （Group Eos）, 1.0% （Group E1.0）, 2.0% （Group E2.0）, 3.0% （Group E3.0） or 5.0% （Group E5.0） of poly-13-hydroxybutyrate （PHB） during their growth and spawning periods, to explore the effect of PHB on the reproductive performance of parents and the development of larvae. The experi- ment was lasted for 192 d to measure the mortality rate, relative percentage of survival（RPS）, weight gain rate（WGR）, specific growth rate （SGR） and cycle of gonadal development of parental shrimps, number of eggs, number of nauplii, stages of larval development and metamorphosis. The results indicated that PHB had an obvious effect on the fecundity of parental shrimps and growth performance of larva. Compared with control group, the mortality rate of broodstock in experimental groups decreased initially and increased subsequently with the increase of PHB concentration, while RPS showed an opposite pattern. The mortality rate of group E2.0 was the lowest among all groups, showing significant difference from that of other groups（P 〈 0.05） except group E1.0 （P 〉 0.05）. WGR of all experimental groups was higher than that of the control group, among which, group E2.0 and group E5.0 had significantly higher WGR than the control （P〈0.05）. However, there was no significant difference in the cycle of gonadal development between the experimental groups and the control group （P 〉 0.05）. The numbers of eggs and nauplii in the experimental groups were higher than those of the control group. And the numbers of eggs and nauplii in group E2.0 were significantly higher than those of the control （P 〈 0.05）, bud showed no significant difference from those of other groups （P 〉 0.05）. However, there was no significant difference in the duration of larval development and metamorphosis among all the groups. In summary, PHB is capable of improving the reproductive performance of parents and the survival and development of larva in F. chinensis, and 2.0% is the optimal concentration of PHB supplemented to the diet.

Study on Reproductive Performance of Improved Hybrid from Chinese Holstein Cattle

In order to overcome the problems such as decline in adaptability, low fertility and few utilization years due to continuously increasing coefficient of inbreeding of Chinese Holstein cattle, three dairy-beef dual-purpose cattle varieties （purebred Simmental, Montbeliard and Fleckvieh） were introduced as the male parents to be hybridized with Chinese Holstein cattle, so as to study the improvement effect in the reproduction performance and milk production performance of the hybrid cattle. The results showed that the first-filial generation of Montbeliard had a very significant difference in gestation period from Chinese Holstein cattle （ P 〈0.01）. The parity of Fleckvieh s first-filial generation had a very significant effect on 305 d milk yield （ P 〈0.01）; and for the first-filial generation of Montbeliard, mating times and open days significantly affected 305 d milk yield （ P 〈0.05）, and its total milk yield had a significant difference from Chinese Holstein cattle （ P 〈0.05）. Comprehensively, the reproduction traits of Montbeliard s first-filial generation are better than other two varieties.

Morphometric Characteristics and Reproductive Performance of Pasundan Cattle in the North Prianganese and Southern South Coast Region

This study aims to determine the morphometric characteristics and reproductive performance of Pasundan cows which are extensively reared on smallholder farms in the coastal areas of the south(Garut,Cianjur,and Sukabumi)and North Priangan(Bogor,Purwakarta,and Sumedang).This research is descriptive research with a qualitative approach.Production characterization was carried out using a simple method,namely by measuring the body surface including shoulder height,chest circumference,body length,and bodyweight of Pasundan cattle.Meanwhile,the reproductive characteristics discuss puberty,service per conception(S/C),conception rate(CR),calving rate,postpartum estrus,postpartum mating,days open(DO),calving interval(CI),calving birth weight,calving rate,and calves weight growth.Data were collected by survey,and the location was determined by purposive sampling in the area of the seed source with the largest population and the random sampling of livestock was determined purposively as many as 30 Pasundan cows from each region.Data were analyzed using quantitative descriptive analysis.The results showed that the morphometric characteristics of Pasundan cattle included mean shoulder height of 123.00±3.06a cm VS 121.34±2.82a in males and 110.34±2.78 vs 108.00±2.14a in females.Body length 115.74±3.30 cm VS 115.34±2.97acm in males and 112.67±2.97cm VS 109.67±1.82 cm in females.Chest circumference 145.67±2.97cm VS 142.67±2.67cm bulls and 136.00±2.95cm VS 131.00±2.92cm in females,Bodyweight 268.0±17.00 kg VS 246.00±7.00a for males and 215.0±15.00 kg VS 194.00±54.00kg in females.As for reproductive characteristics,it shows puberty of 20-24 months.,S/C 1.4-1.6,Conception rate 65-70%,calving rate 62.5-65%,Postpartum Estrus 50-60 days,postpartum mating 72-104 days,day-open 94-126 days and a calving interval of 12-14 months.Calves'birth weight was 18.0-18.5 kg and daily body weight gain ranged from 0.48 to 0.50 kg.It was concluded that the morphometric characteristics and reproductive performance of Pasundan cattle in the Pesisir Selatan area were better than North Priangan.

Effect of Divergent Selection for Plasma very Low Denstity Lipoprotein Concentration on Reproductive Performance in Broiler Chickens

The reproductive performance and abdominal fat of the high VLDL (H-VLDL) and low VLDL (L-VLDL) lines were studied after divergent selection for plasma very low density lipoprotein (VLDL) concentration in broiler chickens at 8 weeks of age. It was shown that the main reproductive traits were higher in L-VLDL line than H-VLDL line. The beneficial correlated responses of the reproductive traits were produced by the selection for plasma VLDL. 1) Plasma VLDL concentration was significantly correlated with abdominal fat (r=0.50, P<0.01), ahich was higher than that with plasma triglyceride concentration. There was a significant difference in abdominal fat between both lines but age increase or food restriction may decrease this difference. The H-VLDL line had about twice as much abdominal fat as had L-VLDL at 8 weeks of age, while its mean body weight was similar to that of the L-VLDL line from birtl to the end of laying. 2) Mortality from apparently stress-related causes by food restriction for H-VLDL line females began to increase from 15 weeks of age and was 21% (38/180) higher compared with 13% (23/180) for L-VLDL line females. 3) Age of 5% Lying for L-VLDL line was 3 days less than that of H-VLDL line, age of 50% Lying was 37 days less for L-VLDL line than H-VLDL line, and the age of laying peak was similiar in both lines. Rate of lay at peak in L-VLDL and H-VLDL lines were 70.3%, 66.4%, respectively. 4) Fertility rate in L-VLDL line was significantly higher than that of H-VLDL line at 27 weeks of age (P=0.01) and there was a little difference in fertility rates between H-VLDL and L-VLDL line during late laying period. There were no significant differences between H-VLDL and L-VLDL lines in of day-old healthy the numbers chicks and hatchabilities of fertile and total eggs wheres mean numbers of healthy day-old chicks per hen were more is L-VLDL line than in H-VLDL line. 5) Under food restriction, egg production was higher in L-VLDL line than in H-VLDL line. It should be emphasized that the rate and amount of egg production in L-VLDL line were both significant higher than in H-VLDL line during early laying period (from 23 to 43 weeks of age, P<0.01). The mean egg production of LF line hens was ll eggs more than that of HF line ones throughtout the laying period (from 23 to 62 weeks of age). 6) Eggs in L-VLDL line were slightly heavier than those in H-VLDL line. Feed conversion (FC) ratio for L-VLDL line was lower than that in H-VLDL line betwen 23 and 62 weeks of age (5.01 and 5.46, respectively), especially FC ratio of L-VLDL line was significantly lower than that of HF line during 23 and 43 weeks of age (P<0.01). Also FC efficiency of breeding hens was higher in L-VLDL line than in H-VLDL line.

Path analysis of desirable traits and evaluation of reproductive performance of Crassostrea sikamea in different ages

Kumamoto oysters(Crassostrea sikamea)are important marine aquaculture shellfish because of their taste and round shell shape.Due to its small size,selective breeding is required to improve its market size,but there are no reports on traits suitable for direction selection and reproductive productivity of Kumamoto oysters of different ages.In this study,path analysis and one-way ANOVA were used to explore the influential indices of oyster body weight and fecundity.The results showed that shell height was the main factor affecting the body weight of Kumamoto oysters at one-year-old and two-year-old,followed by shell length.Body weight was the main factor influencing fecundity,and shell height showed a significant correlation with fecundity.Therefore,shell height should be considered the first parameter for selection when selecting Kumamoto oysters for body weight as the direct selection target.When one-year-old and two-year-old Kumamoto oysters were selected as parents from Xiangshan Bay,hatching parameters and growth parameters of F1 generation larvae were measured.The fecundity and egg diameters were 1.72×10^(6)and 46.60±3.62μm,respectively,which were significantly greater than one-aged oysters(5.86×10^(5),40.26±3.52μm).The hatching parameters(fertilized egg size,fertilization rate,and hatching rate)and larval growth performance(D-stage veliger and veliger)were similar and did not differ significantly(P>0.05),and after metamorphosis,there was also no significant difference in shell height size at 40 days of age(P>0.05).Therefore,there was no significant effect of age on reproduction,larval development,and the early growth of Kumamoto oysters.These results could provide a basis for parental sources and proper traits for Kumamoto oyster selection,which is beneficial to developing and utilizing this excellent germplasm resource.

Impacts of CO_2-driven seawater acidification on survival,egg production rate and hatching success of four marine copepods

Ecological experiments were conducted to examine the effects of seawater containing elevated par- tial pressure of carbon dioxide （p CO2 800 × 10 -6 , 2 000 × 10 -6 , 5 000 × 10 -6 and 10 000 × 10 -6 ） on the survival and reproduction of female Acartia pacifica, Acartia spinicauda, Calanus sinicus and Centropages tenuiremis, which are the dominant copepods in the southern coastal waters of China. The results show that the effects of elevated p CO2 on the survival rates of copepods were species-specific. C. sinicus, which was a macro-copepod, had a higher survival rate （62.01%–71.96%） than the other three species （5.00%–26.67%） during the eight day exposure. The egg production rates of C. sinicus, A. spinicauda and C. tenuiremis were significantly inhibited by the increased p CO2 and the exposure time duration. There were significantly negative impacts on the egg hatching success of A. spinicauda and C. tenuiremis in the p CO2 2 000 × 10 -6 and 10 000 × 10 -6 groups, and, in addition, the exposure time had noticeably impacts on these rates too. This study indicates that the reproductive performances of copepods were sensitive to elevated p CO2 , and that the response of different copepod species to acidified seawater was different. Furthermore, the synergistic effects of seawater acidification and climate change or other pollutant stresses on organisms should be given more attention.

Impact of Different Diets on Adult Tri-Spine Horseshoe Crab,Tachypleus tridentatus

Effective culture and management of adult tri-spine horseshoe crab,Tachypleus tridentatus can ensure that stock enhancement programs and aquaculture systems are maintained.To explore suitable feed for animals during the breeding season,Pacific oyster(Ostrea gigas)(oyster group;OG)and frozen sharpbelly fish(Hemiculter leucisculus)(frozen fish group;FG)were selected to feed 20 T.tridentatus male and female pairs,respectively.At the end of the experiment,intestinal samples were obtained to measure digestive enzymes activities.The intestinal flora were determined by 16S r DNA sequencing.No eggs were observed in the FG and one T.tridentatus adult died.No animals died in the OG,and 9.7×10;eggs were obtained.These results show that oysters are more suitable for the development and reproduction of adult T.tridentatus than frozen fish.Additionally,the digestive enzyme activity analysis revealed that animals in the OG exhibited higher protein digestibility than those in the FG,but no significant differences in lipid and carbohydrate uptake were observed between the groups.Furthermore,the intestinal flora analysis showed that operational taxonomic units(OTUs)and the Chao1 index were significantly higher in the OG than in the FG,but no significant difference was observed in the Shannon or Simpson indices between the groups.Our data indicate that the oyster diet improved the intestinal microbial diversity of T.tridentatus.We hypothesize that nutrients,such as oyster-based taurine,proteins,and highly unsaturated fatty acids,improve protease activity in the T.tridentatus digestive tract,alter the intestinal floral structure,and improve the reproductive performance of T.tridentatus.

Management Practices and Production Constraints of Indigenous Somali Cattle Breed in Shabelle Zone, Somali Regional State, Ethiopia

This study was conducted in Shabelle zone of Somali Regional State to assess management practices and production constraints of indigenous Somali Cattle. A total of 200 household heads were selected from four cattle potential districts;Dhanan, Ber’ano, Godey & Adadle. The relevant information was collected through semi-structured questionnaire, focus group discussion, key informants interview, and personal observations. Majority of the respondents were illiterate. The average cattle holding size was 8.97 heads/household and cattle were mainly kept for milk production. The major feed resources in the study area were natural pasture and crop residue, and communal grazing was the most important feeding system in the area. Feed shortage was a problem hindering cattle production in the study area during dry season mainly January up to March. Animals traveled long distances to watering points (>5 km) during dry season, while in wet season, animals were watered in nearby water sources. Cattle housing was open kraal fenced with the thorned plenty acacia trees and calves were housed separately from other cattle. Breeding in the study area was uncontrolled and was bred with their own or neighbors’ bull. Age at first mating, age at first calving and calving interval were 3.25 years, 4.05 years and 16.56 months, respectively. The daily milk yield and lactation length were 2.22 liters and 8.07 months, respectively. The production and reproduction performance of Somali cattle was relatively higher than other local breeds in the country mainly in terms of milk yield and fertility potential under the existing environmental conditions. The major constraints of cattle production were feed shortage, disease, water scarcity, lack of veterinary services, marketing problem and predator. Among those constraints, inadequate supply of quality feed, diseases and water shortage were the main reasons for low productivity of cattle and are the major factors limiting productivity. Therefore, to sustain the production system in the study areas, it is recommended to improve the current condition of communal rangelands through management of degraded areas by awareness creation on the value of these common resources and development of rules and regulation to sustain the existing resource and implement over the utilization of communal/pastoral rangeland management systems to reduce constraints such as shortage of feed, drought and grazing land deterioration which perpetuated through time due to land-use changes and seasonal fluctuation).