Large‑scale transcriptomic and genomic analyses reveal a novel functional gene SERPINB6 for chicken carcass traits

Background Carcass traits are crucial indicators of meat production efficiency.However,the molecular regulatory mechanisms associated with these traits remain unclear.Results In this study,we conducted comprehensive transcriptomic and genomic analyses on 399 Tiannong partridge chickens to identify key genes and variants associated with carcass traits and to elucidate the underlying regulatory mechanisms.Based on association analyses with the elastic net(EN)model,we identified 12 candidate genes(AMY1A,AP3B2,CEBPG,EEF2,EIF4EBP1,FGFR1,FOXD3,GOLM1,LOC107052698,PABPC1,SERPINB6 and TBC1D16)for 4 carcass-related traits,namely live weight,dressed weight,eviscerated weight,and breast muscle weight.SERPINB6 was identified as the only overlapping gene by 3 analyses,EN model analysis,weighted gene co-expression network analysis and differential expression analysis.Cell-level experiments confirmed that SERPINB6 promotes the proliferation of chicken DF1 cells and primary myoblasts.Further expression genome-wide association study and association analysis indicated that rs317934171 is the critical site that enhances SERPINB6 expression.Furthermore,a dual-luciferase reporter assay proved that gga-miR-1615 targets the 3′UTR of SERPINB6.Conclusions Collectively,our findings reveal that SERPINB6 serves as a novel gene for chicken carcass traits by promoting fibroblast and myoblast proliferation.Additionally,the downstream variant rs317934171 regulates SERPINB6 expression.These results identify a new target gene and molecular marker for the molecular mechanisms of chicken carcass traits.

Technical-Economic Performance, Carcass and Meat Quality of COBB500 Broilers Fed Rations Incorporating Mango By-Product Feeds in Ivory Coast (West Africa)

The study evaluated the growth performance and carcass quality of COBB500 broilers fed two experimental rations incorporating feed and mango fine ED10 for a batch of 83 birds, ED20 (batch of 83 birds) in comparison with a commercial control ration CCD (84 birds). For this purpose, 250 day-old chicks of this breed were purchased in Korhogo and transported to Tengréla in Ivory Coast for rearing. The results show that substituting mango provender ans and mango seed flour for maize resulted in rations with costs per kgMS of 215.35FCFA, 2016.93FCFA and 320FCFA for the ED10, ED20 and CCD rations respectively. The production costs per kg of chicken (FCPkgLW) of the CCD ration were significantly higher than those of the ED10 and ED20 (p 0.05). ADGs were significantly different and decreasing from CCD, ED20 to ED10 (p 0.05). Average weights at 42nd day for ED20 and CCD were homogeneous (p > 0.05) and significantly higher than for ED10 (p 0.05). By day 49th the average weight of ED20 had reached and exceeded that of CCD by day 42nd. PSLW, HCW and CCW were significantly different and decreasing from CCW, ED20 to ED10 (p 0.05). Average hot (HCY) and cooled (CCY) carcass yields of ED20 and CCD rations were comparable (p > 0.05) and significantly higher than those of ED10 ration (p = 0.009) and 0.003). Average drumstick and neck weights were significantly higher and lower for CCD, ED20 and ED10 (p 0.05). For all other parts of the cut, the average weights of the CCD ration were significantly higher (p 0.05) than those of the ED20 and ED10 rations, which were homogeneous (p 0.05). The incorporation of mango provender and mango seed flour in broiler rations offers the prospect of reduced production costs, less competition between man and animals over cereals, and lean meat production that is more appreciated than that of chickens fed conventional feed. As it stands, the ED20 ration can be recommended as a growth diet for broilers. It would be necessary to determine the levels of anti-nutritional substances in mango feeds and to assess the in vivo digestibility of mango ingredients and the diets incorporating them.

First Known Case of Carcass Guarding by Black Kite (Milvus migrans) in Urban Landscape, North India

Behavioral traits of species can play an important role in the functioning of the ecosystem and in evolving behavioural adaptations to survive according to environmental conditions.This note documents evidence of adding a rare observation by providing photographic evidence of the entanglement of a carcass of a juvenile Black Kite(Milvus migrans)from a nest and the use of nest by an adult individual,guarding the carcass.Documenting such behavior contributes to our understanding of the natural history and management of native species in an urban environment.Further,scientific studies/observations are needed to be conducted to reach some conclusion as to why species perform such behaviour.

Strategies to improve genomic predictions for 35 duck carcass traits in an F2 population

Background Carcass traits are crucial for broiler ducks,but carcass traits can only be measured postmortem.Genomic selection(GS)is an effective approach in animal breeding to improve selection and reduce costs.However,the performance of genomic prediction in duck carcass traits remains largely unknown.Results In this study,we estimated the genetic parameters,performed GS using different models and marker densi-ties,and compared the estimation performance between GS and conventional BLUP on 35 carcass traits in an F2 population of ducks.Most of the cut weight traits and intestine length traits were estimated to be high and moder-ate heritabilities,respectively,while the heritabilities of percentage slaughter traits were dynamic.The reliability of genome prediction using GBLUP increased by an average of 0.06 compared to the conventional BLUP method.The Permutation studies revealed that 50K markers had achieved ideal prediction reliability,while 3K markers still achieved 90.7%predictive capability would further reduce the cost for duck carcass traits.The genomic relationship matrix nor-malized by our true variance method instead of the widely used 2pi(1-pi)could achieve an increase in prediction reliability in most traits.We detected most of the bayesian models had a better performance,especially for BayesN.Compared to GBLUP,BayesN can further improve the predictive reliability with an average of 0.06 for duck carcass traits.Conclusion This study demonstrates genomic selection for duck carcass traits is promising.The genomic prediction can be further improved by modifying the genomic relationship matrix using our proposed true variance method and several Bayesian models.Permutation study provides a theoretical basis for the fact that low-density arrays can be used to reduce genotype costs in duck genome selection.

Effects of carcass weight, sex and breed composition on meat cuts and carcass trait in finishing pigs

Pork cutting is a very important processing in promoting economic appreciation across the swine business chain. The goal of this research is to determine the proportion and weight of meat cuts, as well as to analyze the effects of carcass weight, sex and breed composition on meat cuts. Simultaneously, we investigate the correlation between meat cuts, carcass traits and meat quality traits. To assess 17 meat cut traits, 12 carcass traits and 6 meat quality traits, we sample 2 012 pigs from four breeds, including Landrace(LD), Yorkshire(YK), Landrace Yorkshire(LY), and Duroc Landrace Yorkshire(DLY). The results showed that carcass weight, sex and breed composition have significant effects on the weight and proportion of most meat cuts. The proportion of cuts for muscle and bone decrease as carcass weight grows, whereas the proportion of cuts for fat increases. Moreover, the thickness of four-point backfat was significantly increasing(P<0.001) with increase of carcass weights, indicating that large amount of intaking energy in the late finishing stage was used for fat deposition. Besides, the proportion of Shoulder cut(SC) and Back fat(BF) in barrows was significantly higher(P<0.001) than that in sows, whereas the Leg cut(LC) showed the opposite trend. The Loin(LO) proportion and Loin muscle area(LMA) of barrows were significantly lower(P<0.001), but the proportion of fat areas in the image(PFAI) and visual marbling score(VMS) were significantly higher(P<0.001) than those of sows, respectively. In terms of breeds, LD had the longest straight carcass length, significantly longer(P<0.001) than the other three breeds, which partially explains why LD had the largest proportion of the Middle cut(MC). Moreover, the proportion of SC in DLY was the highest. Last but not least, the correlations between the proportions of most meat cuts, and also between meat cuts and meat quality or carcass traits were low or not significant(P>0.05). The effects of carcass weight, sex and breed composition on the meat cuts, meat quality and carcass traits are breed and growth stage dependent. It also reflects the asynchrony of the growth curve between different sexes. Our results laid an important foundation for breeding pig carcass cuts and composition.

Genetic dissection and genomic prediction for pork cuts and carcass morphology traits in pig

Background As pre-cut and pre-packaged chilled meat becomes increasingly popular,integrating the carcasscutting process into the pig industry chain has become a trend.Identifying quantitative trait loci(QTLs)of pork cuts would facilitate the selection of pigs with a higher overall value.However,previous studies solely focused on evaluating the phenotypic and genetic parameters of pork cuts,neglecting the investigation of QTLs influencing these traits.This study involved 17 pork cuts and 12 morphology traits from 2,012 pigs across four populations genotyped using CC1 PorcineSNP50 BeadChips.Our aim was to identify QTLs and evaluate the accuracy of genomic estimated breed values(GEBVs)for pork cuts.Results We identified 14 QTLs and 112 QTLs for 17 pork cuts by GWAS using haplotype and imputation genotypes,respectively.Specifically,we found that HMGA1,VRTN and BMP2 were associated with body length and weight.Subsequent analysis revealed that HMGA1 primarily affects the size of fore leg bones,VRTN primarily affects the number of vertebrates,and BMP2 primarily affects the length of vertebrae and the size of hind leg bones.The prediction accuracy was defined as the correlation between the adjusted phenotype and GEBVs in the validation population,divided by the square root of the trait’s heritability.The prediction accuracy of GEBVs for pork cuts varied from 0.342 to 0.693.Notably,ribs,boneless picnic shoulder,tenderloin,hind leg bones,and scapula bones exhibited prediction accuracies exceeding 0.600.Employing better models,increasing marker density through genotype imputation,and pre-selecting markers significantly improved the prediction accuracy of GEBVs.Conclusions We performed the first study to dissect the genetic mechanism of pork cuts and identified a large number of significant QTLs and potential candidate genes.These findings carry significant implications for the breeding of pork cuts through marker-assisted and genomic selection.Additionally,we have constructed the first reference populations for genomic selection of pork cuts in pigs.

Prediction of Load-Displacement Curve of Flexible Pipe Carcass Under Radial Compression Based on Residual Neural Network

The carcass layer of flexible pipe comprises a large-angle spiral structure with a complex interlocked stainless steel cross-section profile, which is mainly used to resist radial load. With the complex structure of the carcass layer, an equivalent simplified model is used to study the mechanical properties of the carcass layer. However, the current equivalent carcass model only considers the elastic deformation, and this simplification leads to huge errors in the calculation results. In this study, radial compression experiments were carried out to make the carcasses to undergo plastic deformation. Subsequently, a residual neural network based on the experimental data was established to predict the load-displacement curves of carcasses with different inner diameter in plastic states under radial compression.The established neural network model’s high precision was verified by experimental data, and the influence of the number of input variables on the accuracy of the neural network was discussed. The conclusion shows that the residual neural network model established based on the experimental data of the small-diameter carcass layer can predict the load-displacement curve of the large-diameter carcass layer in the plastic stage. With the decrease of input data, the prediction accuracy of residual network model in plasticity stage will decrease.

Carcass and Meat Characteristics of Hararghe Highland Bull after Draught Work Service

The objectives of the study were to examine the effects of draught work on carcass characteristics, meat yield potential, and distribution along primal cuts in Hararghe highland bulls fed on net energy requirement basis. Twelve bulls were sorted into three groups of four animals each and assigned to three treatment hours: control (0), 4, or 6, using a complete randomized design (CRD). The results of the study show that there are no significant differences (p > 0.05) in slaughter weight, hot carcass weight (HCW), chilling loss, total edible and non-edible offal, fat thickness (FT), deboned meat yield (kg), meat to bone ratio, muscle distribution, and proportion of kidney, pelvic, and heart fat (KPH%) among the treatment groups. However, the hot carcass-based dressing percentage was significantly lowered (p < 0.05) in bulls that work 4 or 6 hours a day. Meat yield was strongly correlated with HCW (r = 0.74) and FT (r = 0.73). Therefore, the number of hours the bull spent on draught work did not negatively impact meat yield or quality. Consequently, the research suggests that utilizing Hararghe highland bulls for draught service, four or six hours a day is viable for dual advantages: crop cultivation and marketable carcass.

Study on Carcass Traits of Changtai Yak

For studying the germplasm charactedsUcs and carcass traits of Changtai yak, 8 adult yaks （5 male, 3 female） were selected and tested. The results showed that the pre-slaughter weight of the adult male and female Changtai yak was 364.32 and 266.83 kg, respectively, which presented extremely significant difference （P〈0.01）. The carcass weight, net bone weight net meat weight, and the ratio of bone to meat also showed extremely significant difference （P〈O.01）, which were 186.60 and 125.67 kg, 39.74 and 25.00 kg, 147.84 and 100.83 kg, 1：3.73 and 1： 4.03, respectively. The dressing percentage had significant difference which was 51.15% and 49.34%, respectively （P〈0.05）. The neat meat percentage and carcass meat production rate showed no significant difference which were 40.54% and 37.66%, 79.29% and 80.24%, respectively （P〉0.05）. It indicated that Changtai yak has better growth performance and meat performance potential, and worth of further studying and breeding.

Carcass and Meat Characteristics of Bulls from Arsi, Boran, Harar and Holstein Frisian Crosses Cattle Breeds Finished under Similar Level of Concentrate Supplementation

A study was conducted to evaluate the effect of age and breeds (Arsi, Borana, HF-Cross and Harar) on carcass and meat characteristics of bulls finished under similar feeding conditions. The feeding experiment was conducted for 90 days at Beef farm of Haramaya University. In this experiment, 24 bulls were fed with roughage (60%) which contained grass hay and wheat straw and concentrate (40%) which contained wheat bran, noug (gucia abysica) cake, maize grain, limestone, salt and ruminant premix. The bulls were transported to Bishoftu ELFORA export abattoir for slaughter following the procedure of the abattoir. The result of the study revealed that the average slaughter weight, hot carcass weight, cold carcass weight, shrink loss, commercial dressing and true dressing percentage were 179.1 kg, 86.8 kg, 82.7 kg 4.7%, 48.8% and 78.3%, respectively. Total edible and nonedible offal were significantly (P < 0.01) influenced by breed and age. Pelvic fat was significantly (P < 0.01) influenced by breeds. Meat yield percentages of Arsi, Boran, Harar, and HF-crossbred were 78.1%, 77%, 72.8% and 77.2% respectively. Meat yield was predicted from fat thickness and ribeye area with 61% accuracy. Arsi bulls attained the highest (78%) meat yield at early age but decreased by 0.713 rate as age of animals advanced by one digit whereas the meat yield from other breeds showed increment in meat yield percentage with the rate of 1.98, 1.1 and 0.1 for cross, Borana and Harar breed bulls, respectively as age advanced. Yield from fore shank, sirloin, top and bottom sirloin primal cuts were affected by breed. Arsi breed had higher meat bone ration than cross breed. Retailed meat yield was significantly (P < 0.001) predicted from rib area and subcutaneous fat thickness (P < 0.001) with a coefficient of determination 61%, from live animal trait and primal cuts with a coefficient of determination 89.56% and 94.78% respectively. Arsi bulls can be used for beef purpose at 2 - 3 years, as the meat percentage decreases thereafter;while bulls from Boran, cross breed and Harar breeds can be used up to 5 years of age. Meat to bone ratio indicated that HF-Crossbred was less appropriate for beef purpose than other breed bulls in this study. The rate of pH decline was not influence (P > 0.05) by age and breed in the current study.

Expression of GHR, IGF-I, IGF-IR and IGFBP-3 Genes in Leg Muscles of Taihu Goose and Wanxi White Goose and Correlation between Their Expression and Carcass Traits

[Objective] This study aimed to explore the effects of IGFs system on the growth of goose skeletal muscles. [Method] Quantitative fluorescence PCR technique was adopted to study the variety- and gender-specificity in the expression of GHR, IGF-I, IGF-IR and IGFBP-3 genes in leg muscles of 70-day-old Taihu goose and Wanxi white goose, and the correlation between their expression and carcass traits was also investigated. [Resull] There was no variety difference in the expression of GHR, IGF-t, IGF-IR and IGFBP-3 genes in leg muscles of Taihu goose and Wanxi white goose, but there were significant variety differences in the body weight and leg muscle weight. There were no gender difference in the body weight, leg muscle weight and the rate of leg muscles; except IGF-I mRNA level that was significantly higher in male Taihu goose than in female ones（P=0.032）, there was no gender dif- ference in the expression of other three genes. Among the four tested genes, only IGFBP-3 mRNA exhibited an extremely significantly positively correlation with the rate of leg muscles, suggesting that IGFs may play a role in regulating the growth of leg muscles via IGFBP-3 system in 70-day-old goose. [Conclusion] This study provides theoretical basis for research in the skeletal growth and development.

An Investigation on the Carcass Percentage of Anatolian Grey Breed in Edirne Province

In this study it is aimed to investigate live weight and carcass traits of Anatolian Grey and Anatolian Grey x Brown Swiss crossbred in raised Edirne and Kesan. In this study the authors used 51 Anatolian Grey bulls, 22 Anatolian Grey heifers and 63 Anatolian Grey x Brown Swiss crossbred bulls. 136 animals in 2-3 years old were used present study. The live weights were found 446.375 ± 20.87 and 508.29 ± 11.88 kg for Anatolian Grey bull and Anatolian Grey x Brown Swiss crossbred bull respectively. Carcass percentage were found 60.57%, 46.84%, 56.87% and the correlation coefficient were calculated between live weight and carcass percentage 0.98, 0.80 and 0.94 for Anatolian Grey bulls, Anatolian Grey heifers and Anatolian Grey x Brown Swiss crossbred bulls, respectively.

Exploration of Urinary Creatinine to Determine the Carcass and Its Protein Weight in Beef Cattle

This study was aimed to explore the use of creatinine as indicator to predict carcass and its protein weight in beef cattle. Eight Ongole crossbred cattle with initial body weight ranged at 133.5-228 kg and age of 6-18 months were used in this study. The cattle were fed Napier grass ad libitum and concentrate feeding for three months prior to be slaughtered. Concentrate feeding was consisted of rice bran and soybean meal which was provided to fulfill dry matter requirement at 2.1% of body weight （BW）. The availability of creatinine for prediction indicator was done by evaluate the correlation between the amount of daily urinary creatinine and the carcass and its protein weight. Carcass and its protein weight were measured by slaughtering the cattle, and chemically analyzed for determining protein content of carcass. The results showed that creatinine excreted in urine have a strong correlation with the cattle body weight （r = 0.88）, carcass weight （r = 0.67）, body protein （r = 0.70） and carcass protein （r = 0.72）. The conclusion of this study is creatinine excreted in urine have a strong relationship with the carcass and its protein, and therefore could be used to predict the carcass and its protein weight of beef cattle.

Using a Surface Plasmon Resonance Biosensor for Rapid Detection of Salmonella Typhimurium in Chicken Carcass

Chicken is one of the most popular meat products in the world. Salmonella Typhimurium is a common foodbome pathogens associated with the processing of poultry. An optical Surface Plasmon Resonance （SPR） biosensor was sensitive to the presence of Salmonella Typhimurium in chicken carcass. The Spreeta biosensor kits were used to detect Salmonella Typhimurium on chicken carcass successfully. A taste sensor like electronic tongue or biosensors was used to basically ＂taste＂ the object and differentiated one object from the other with different taste sensor signatures. The surface plasmon resonance biosensor has potential for use in rapid, real-time detection and identification of bacteria, and to study the interaction of organisms with dif- ferent antisera or other molecular species. The selectivity of the SPR biosensor was assayed using a series of antibody con- centrations and dilution series of the organism. The SPR biosensor showed promising to detect the existence of Salmonella Typhimurium at 1 x 106 CFU/ml. Initial results show that the SPR biosensor has the potential for its application in pathogenic bacteria monitoring. However, more tests need to be done to confirm the detection limitation.

Residual feed intake in beef cattle and its association with carcass traits, ruminal solid-fraction bacteria, and epithelium gene expression

Background: Residual feed intake(RFI) describes an animal’s feed efficiency independent of growth performance.The objective of this study was to determine differences in growth performance, carcass traits, major bacteria attached to ruminal solids-fraction, and ruminal epithelium gene expression between the most-efficient and the least-efficient beef cattle. One-hundred and forty-nine Red Angus cattle were allocated to three contemporary groups according to sex and herd origin. Animals were fed a finishing diet in confinement for 70 d to determine the RFI category for each. Within each group, the two most-efficient(n = 6; RFI coefficient =-2.69 ± 0.58 kg dry matter intake(DMI)/d) and the two least-efficient animals(n = 6; RFI coefficient = 3.08 ± 0.55 kg DMI/d) were selected. Immediately after slaughter, ruminal solids-fraction and ruminal epithelium were collected for bacteria relative abundance and epithelial gene expression analyses, respectively, using real-time PCR.Results: The most-efficient animals consumed less feed(P = 0.01; 5.03 kg less DMI/d) compared with the leastefficient animals. No differences(P > 0.10) in initial body weight(BW), final BW, and average daily gain(ADG) were observed between the two RFI classes. There were no significant RFI × sex effects(P > 0.10) on growth performance.Compared with the least-efficient group, hot carcass weight(HCW), ribeye area(REA), and kidney, pelvic, and heart fat(KPH) were greater(P ≤ 0.05) in the most-efficient cattle. No RFI × sex effect(P > 0.10) for carcass traits was detected between RFI groups. Of the 10 bacterial species evaluated, the most-efficient compared with least efficient cattle had greater(P ≤ 0.05) relative abundance of Eubacterium ruminantium, Fibrobacter succinogenes, and Megasphaera elsdenii, and lower(P ≤ 0.05) Succinimonas amylolytica and total bacterial density. No RFI × sex effect on ruminal bacteria was detected between RFI groups. Of the 34 genes evaluated in ruminal epithelium, the mostefficient cattle had greater(P ≤ 0.05) abundance of genes involved in VFA absorption, metabolism, ketogenesis, and immune/inflammation-response. The RFI × sex interactions indicated that responses in gene expression between RFI groups were due to differences in sex. Steers in the most-efficient compared with least-efficient group had greater(P ≤ 0.05) expression of SLC9 A1, HIF1 A, and ACO2. The most-efficient compared with least-efficient heifers had greater(P ≤ 0.05) m RNA expression of BDH1 and lower expression(P ≤ 0.05) of SLC9 A2 and PDHA1.Conclusions: The present study revealed that greater feed efficiency in beef cattle is associated with differences in bacterial species and transcriptional adaptations in the ruminal epithelium that might enhance nutrient delivery and utilization by tissues. The lack of RFI × sex interaction for growth performance and carcass traits indicates that sex may not play a major role in improving these phenotypes in superior RFI beef cattle. However, it is important to note that this result should not be considered a solid biomarker of efficient beef cattle prior to further examination due to the limited number of heifers compared with steers used in the study.

Effects of Dietary Net Energy Density and Standardized Ileal Digestible Lysine: Net Energy Ratio on the Performance and Carcass Characteristic of Growing-Finishing Pigs Fed Low Crude Protein Supplemented with Crystalline Amino Acids Diets

Two 3×3 factorial design trials with 1 080 of Yorkshire×Landrace×Duroc barrows were conducted to investigate the effects of dietary net energy （NE） density and standardized ileal digestible （SID） lysine：NE ratio on the performance of growing- finishing pigs and carcass characteristic of finishing pigs fed low crude protein （CP） supplemented with crystalline amino acids （CAA） diets. Low CP corn-soybean meal basal diets （14% for Exp. 1 and 11% for Exp. 2） supplemented with crystalline lysine, methionine, threonine, and tryptophan were formulated. Nine treatments with increasing NE density and SID lysine：NE ratio were used in each trial （Exp. 1： 9.66, 9.87, and 10.08 MJ kg-1 NE, 0.89, 0.96, and 1.03 g MJ-1 SID lysine： NE; Exp. 2： 9.83, 10.04, and 10.25 MJ kg-1 NE, 0.69, 0.76, and 0.83 g MJ-1 SID lysine：NE）. In Exp. 1, we observed that the average daily gain （ADG） for barrows that received the diet containing 9.87 MJ kg-1 NE was significantly higher than that of barrows fed a 9.66 MJ kg-1 NE diet （P0.05）, but no difference was observed when compared with barrows that received a diet containing 10.08 MJ kg-1 NE （P0.05）. The ADG was affected both linearly （P0.05） and quadratically （P0.05） as the SID lysine：NE ratio increased. The NE density or SID lysine：NE ratio and their interaction had no effect on the average daily feed intake （ADFI） and serum urea nitrogen （SUN） （P0.05）. The feed to gain ratio （F：G） decreased （linearly, P0.05; quadratically, P0.05） as the NE density or SID lysine：NE ratio increased, but no interaction of NE density and SID lysine： NE ratio on the F：G. In Exp. 2, the dietary NE density both linearly （P0.05） and quadratically （P0.05） affected the ADG and F：G. Barrows that received a diet containing 10.04 MJ kg-1 NE had a greater ADG （P0.05） than barrows that received a 9.83 MJ kg-1 diet, but there was no difference （P0.05） as compared with barrows that received a diet containing 10.25 MJ kg-1 NE. F：G was significantly higher （P0.05） for barrows that received a 9.83 MJ kg-1 diet when compared with barrows that received the other two diets. The ADG was significantly decreased （P0.05） for pigs that received a diet containing 0.69 g MJ-1 SID lysine：NE ratio when compared with pigs fed a diet containing 0.76 or 0.83 g MJ-1 SID lysine：NE ratio. The NE density or SID lysine：NE ratio and their interaction had no effect on the average daily feed intake, SUN, and carcass characteristic for finishing barrows （P0.05）. The overall results of the two experiments indicated that barrows that received the diet with the dietary CP level reduced 4 percentage units compared the NRC （1998） recommendations. Maximized the best performance with NE density and SID lysine：NE ratio were 9.87 MJ kg-1, 1.03 g MJ-1 NE for 20-50 kg pigs, and 10.04 MJ kg-1, 0.76 g MJ-1 NE for 60-100 kg pigs, respectively.

Studies on Reducing Nitrogen Excretion: Ⅰ. Net Energy Requirement of Finishing Pigs Maximizing Performance and Carcass Quality Fed Low Crude Protein Diets Supplemented with Crystalline Amino Acids

Two experiments were conducted to in- vestigate the effects of net energy （NE） level on the performance and carcass traits of finishing pigs fed low crude protein （CP） diets supplemented with crystalline amino acids （CAA）. A total of 216 （Exp. 1） and 360 （Exp. 2 ） barrows （ Yorkshire × Landrace× Duroc ） were allotted to one of six treatments （n =6）. The experimental diets were based on corn and soybean meal, and consisted of a high-CP diet that contained approximately 16% CP and 2.50 Mcal/kg of NE as well as five low-CP diets in which the CP level of the diet was reduced by approximately four percentage units but was supplemented with crystalline lysine, methionine, threonine, and tryptophan. The low CP diets provided 2.64, 2.58, 2.50, 2.42, or 2.36 Mcal/kg in Exp. 1 as well as 2.45, 2.40, 2.35, 2.30, or 2.25 Mcai/kg in Exp.2. In Exp. 1, a linear （P=0.03） increase in weight gain was observed with decreasing NE level while the ratio of gain to feed was unaffect- ed （P 〉 0.05） by NE level. There was a linear in-crease （P = 0.01 ） in the percentage of fat-free lean and a linear decrease （ P = 0.03 ） in the percentage of total fat with decreasing NE levels. In Exp. 2, a sig- nificant quadratic （ P = 0.03 ） effect of NE level was observed for weight gain. The ratio of gain to feed demonstrated a significant （P 〈0.01 ） quadratic effect with pigs fed 2.35 and 2.40 Mcal/kg of NE, Pigs fed the diet containing 2.40 Mcal/kg of NE had the lowest percentage of total fat （36. 95% ） and the highest percentage of fat-free lean （49.36%）. The overall results of these experiments indicate that feed- ing either a surplus or a deficiency of NE is detrimen- tal to both pig performance and carcass composition when low CP diets supplemented with CAA are fed. Our results indicate that when the CP content of the diet is reduced by four percentage units and the diet is properly supplemented with CAA, maximum per- formance and carcass quality will be obtained if the diet provides approximately 2.42 Mcal/kg of NE.

Correlation Analysis on Single Nucleotide Polymorphism of CAPN1 Gene and Meat Quality and Carcass Traits in Chickens

The selection of meat quality has received considerable focus in chicken breeding. This study was aimed at investigating the effect of CAPN1 gene on meat quality traits in chicken populations. Primer pairs for 3 UTR in CAPN1 were designed from database of chicken genomic sequence. Polymorphisms were detected using PCR-SSCP and DNA sequencing. A mutation at position 9 950 nt （G/A, locus A） was found among individuals in each population. The allele and genotype frequencies significantly differed among eight lines with higher frequencies of allele A2 and genotype AIA2 （P〈0.01）. The least square analysis showed that there was significant difference （P 〈 0.05） in muscle fiber density and some carcass traits among genotypes and that the breast muscle fiber density （BFD） of birds ofAIA1 genotype was significantly higher （P〈0.05） than that of birds ofA2A2 genotype. It was concluded that the CAPN1 gene was the major gene affecting the muscle fiber traits of chicken or was linked with the major gene. These results were useful for studying the molecular mechanism that influences meat traits and were used as the base of molecular-assisted selection to meat quality traits. So, this site may be a potential marker affecting the muscle traits of chickens.

Supplementation of different fat sources affects growth performance and carcass composition of finishing pigs

Background: There are various fat sources with different energy values and fatty acid compositions that may affect growth performance and carcass composition of grow-finishing pigs. A higher net energy was recently reported in choice white grease compared with soybean oil. Therefore, two experiments were conducted to determine whether practical responses confirm that difference between choice white grease and soybean oil, and to extend the observations to other fat sources.Results: In Exp. 1, pigs fed fats had lower(P < 0.05) average daily feed intake in phase II and overall period,greater(P < 0.05) gain:feed in phase I, phase II, and overall period than pigs fed the control diet. Pigs fed fats tended(P = 0.057) to have thicker backfat depth at the last rib than those fed control. Pigs fed 6% fats had greater(P < 0.01) gain:feed in phase II and overall period than pigs fed 3% fats. During phase I, pigs fed choice white grease grew faster(P < 0.05) than pigs fed soybean oil. In Exp. 2, pigs fed dietary fats(soybean oil, choice white grease, animal-vegetable blend, palm oil, or tallow) had greater(P < 0.01) gain:feed in each phase and overall period, greater(P < 0.01) average daily gain in phase I, but lower(P < 0.01) average daily feed intake in phase II an overall than pigs fed the control diets. The choice white grease also increased(P < 0.05) average daily gain during phase I compared with soybean oil. Pigs fed palm oil had thicker(P < 0.05) backfat depth at the 10 thrib than those fed soybean oil, animal-vegetable blend, or tallow.Conclusions: Inclusion of 6% dietary fat improved feed efficiency of finishing pigs, while different fats produced different practical results that may be consistent with their different energy values. Results from the early stage indicate that dietary fats with relatively more saturated fatty acids may provide greater energy than those with relatively more unsaturated fatty acids for growing pigs.

Genome-Wide Association Study for Certain Carcass Traits and Organ Weights in a Large White×Minzhu Intercross Porcine Population

Porcine carcass traits and organ weights have important economic roles in the swine industry. A total of 576 animals from a Large White×Minzhu intercross population were genotyped using the Illumina PorcineSNP60K Beadchip and were phenotyped for 10 traits, speciifcally, backfat thickness （6-7 libs）, carcass length, carcass weight, foot weight, head weight, heart weight, leaf fat weight, liver weight, lung weight and slaughter body weight. The genome-wide association study （GWAS） was assessed by Genome Wide Rapid Association using the mixed model and regression-genomic control approach. A total of 31 single nucleotide polymorphisms （SNPs） （with the most signiifcant SNP being MARC0033464, P value=6.80×10-13） were located in a 9.76-Mb （31.24-41.00 Mb） region on SSC7 and were found to be signiifcantly associated with one or more carcass traits and organ weights. High percentage of phenotypic variance explanation was observed for each trait ranging from 31.21 to 67.42%. Linkage analysis revealed one haplotype block of 495 kb, in which the most signiifcant SNP being MARC0033464 was contained, on SSC7 at complete linkage disequilibrium. Annotation of the pig reference genome suggested 6 genes （GRM4, HMGA1, NUDT3, RPS10, SPDEF and PACSIN1） in this candidate linkage disequilibrium （LD） interval. Functional analysis indicated that the HMGA1 gene presents the prime biological candidate for carcass traits and organ weights in pig, with potential application in breeding programs.