Meat-type Breeds Research Articles

Development of Breed Traceability for Autochthonous Attappady Black Goats of South India

Attappady Black goats, a meat-type breed raised by the tribal communities of the Attappady hill ranges in Kerala, India, play a pivotal role in the region’s economy, heavily contributing to the livelihoods of its socially disadvantaged population. This study aimed to develop and validate a set of breed-specific genetic markers to enable the precise differentiation of Attappady Black goats from Malabari goats. Breed genetic traceability for Attappady Black goats was developed by adopting deterministic approach using breed specific markers. High throughput genome-wide SNP genotypic data of reference goat population (24 each from Attappady Black and Malabari) obtained by Illumina Goat SNP50 BeadChip genotyping was used to identify candidate breed specific markers. Among the 605 numbers of putative Attappady breed specific markers identified in the reference population, nine putative Attappady breed specific markers were selected and were validated for breed specificity by converting them into Polymerase Chain Reaction -restriction fragment length polymorphism (PCR-RFLP) markers and genotyped in large sample goat population of 447 goats (246 Attappady Black and 201 Malabari). On validation, four markers retained their breed specificity with probability of identification (Pi) ranging from 0.24 to 0.66. Panel of four Attappady Black breed specific markers yielded Pi of 0.92 with a probability of misjudgement (Pm) of 0.04. These breed-specific markers hold significant potential for facilitating breed traceability thus ensuring their conservation and enhancing the socioeconomic status of the tribal communities that rely on them. Future research should focus on the broader application of these markers in routine breed authentication and in marketing niche livestock products.

Ovomucoid gene polymorphism and its influence on quality changes at various storage timepoint of eggs from two strains of Japanese quail

During storage, irreversible changes occur in eggs, resulting in a decline in their quality, predominantly affecting the albumen. Ovomucoid, a major protein found in egg white, belongs to the Kazal-type serine proteinase inhibitors and serves to protect the embryo from microorganisms. Notably, in chicken eggs, it is a significant allergen. There is a possibility that its polymorphism also influences the quality and stability of table eggs. Hence, this study aimed to evaluate the potential effect of polymorphism in the ovomucoid gene and protein on quality changes during the storage of eggs derived from 2 strains of Japanese quail, encompassing various utility types. Eggs from selected females of laying and meat-type breeds were stored for 14 wk, with egg quality traits assessed 10 times during this duration. DNA was isolated from each female, and sequencing was conducted on all exons of the ovomucoid gene. In total, 5 SNPs were identified in exons and adjacent intronic sequences, with SNP1 (13:12355585), SNP4 (13:12356594), and SNP5 (13:12358538) leading to amino acid substitutions in the ovomucoid protein. Notably, all SNPs except SNP5 were identified in the ovomucoid gene of Japanese quail for the first time. The results demonstrated that in the F33 strain, SNP1, SNP3, and SNP4 exhibited significant associations with egg weight, whereas in the S22 strain, SNP5 significantly affected yolk color and various eggshell quality traits, including eggshell weight, eggshell thickness, and breaking strength, throughout the storage period. Furthermore, a haplotype block containing 2 SNPs (3 and 4) was identified, exhibiting 2 distinct haplotypes that significantly affected egg weight, eggshell weight, and breaking strength at various storage time points during egg quality analyses. These findings provide novel insights into the genetic basis of egg quality during storage and have the potential to be integrated into breeding programs for these strains.

The relationship between lysozyme gene polymorphism and quality changes during the storage of eggs derived from 2 commercial strains of Japanese quail

During the storage irreversible changes occur in eggs that result in a deterioration of their quality. The most significant changes affect the albumen. One of the major proteins of albumen present in egg white is lysozyme, which protects the embryo from microorganisms. This enzyme also contributes to the qualitative characteristics of albumen. It is possible that its polymorphism also affects the quality and stability of the obtained raw material that is, table eggs. Therefore, the aim of this study was to assess the potential effect of polymorphism in the lysozyme gene and protein on the quality changes during the storage of eggs derived from 2 genetic strains of Japanese quail belonging to various utility types. Eggs from selected females of laying and meat-type breeds were stored for 14 wk. During this period the egg quality traits were evaluated 10 times. DNA was isolated from each female and all exons of the lysozyme gene had been sequenced. In total, fourteen SNPs' and one 4-bp indel mutation were identified in exons and adjacent intronic sequences, among which SNP1 (1:32140723) resulted in a substitution of lysine with glutamine (Q21K). The results showed that SNP1 (strain S22), as well as the SNP2, SNP5, SNP7, SNP8, SNP10, SNP11, SNP12 and SNP13 were significantly associated with breaking strength during egg storage in both investigated Japanese quail strains. Furthermore, a 3 haplotype blocks containing nine SNPs (2, 5, 6, 7, 8, 10, 11, 12 and 13) were identified. These blocks displayed 8 distinct haplotypes that had significant association with breaking strength at all storage time points where egg quality analyses were performed. The study also revealed significant effects of breed and storage time on the egg quality traits. These results provide new insights into the genetic basis of egg quality during storage and could be incorporated into the breeding programs involving these strains.

Growth, haemato-biochemical, hormonal and disease characteristics in Black Bengal goats: a review.

The goats have been considered one of the noteworthy animals to provide food security and could promote socio-economic upliftment under challenging climatic scenarios in the coming decades, particularly in the tropics. Black Bengal goat (BBG) is one of the recognised native meat-type breeds of hot-humid tropics with distinguished characteristics, including superior-quality meat, excellent skin and high prolificacy. Smaller body mass, lower metabolic rate and efficient utilisation of high-fibre forages enable BBG to adapt to a wide range of harsh climates in the tropics. The BBG can maintain physiological homeostasis efficiently in terms of electrolyte profile, endocrine functions and haemato-biochemical traits in different life phases, including the gestation period, even in high-saline coastal areas of hot-humid tropics. Crossbreeding to improve its growth rate has been attempted, but the prolificacy has been decayed. This review is intended to attract global attention to the adaptive potentialities of Black Bengal goats in terms of growth and production, haemato-biochemical, endocrinological, salt tolerance and disease characteristics that could be an asset of climate-resilient agricultural farming.

Effect of feeding corn silage on semen quality and spermatogenesis of bulls.

Bovine reproduction, including male fertility traits like semen quality, are influenced by a variety of different factors like breed, nutrition, environment, and feeding management. Diet in a crucial determinant, and in this regard although corn silage is generally considered to be a favorable roughage for fattening meat type breeds, it tends to have a negative impact on semen quality. In the current study, alfalfa hay was substituted by corn silage as a roughage source in the diet of bulls to investigate its effects on the fertility of breeding bulls. A feeding trail spanning 140 days was conducted, with semen collection occurring twice a week commencing 60 days after the start of trial. Semen quality parameters, serum antioxidant indexes, sex hormone content in semen, rumen microflora, and sperm transcriptome were characterized. Feeding corn silage enhanced host antioxidant capacity, significantly decreased spermatozoal motility and increased sperm deformity rate in bulls. Furthermore, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) content in semen were significantly decreased (P < 0.05), and the inhibin B (INHB) content was significantly increased (P < 0.01). Feeding corn silage led to significant changes in the diversity of rumen microbiota of cattle at the phylum and genus levels, some of which were significantly correlated with semen quality. Subsequent RNA sequencing indicated that DHH and PITHD1, two genes related to sperm and reproductive development, were differentially expressed, and enrichment analysis also identified several pathways and biological functions relevant to sperm development and reproduction. These results indicate that feeding corn silage modulates semen quality via different pathways. Firstly, corn silage metabolites likely affect the secretion of INHB through the testicular capillaries, which affects semen quality by regulating genes involved in spermatogenesis. Secondly, low lignin content in silage corn appears to reduce abundance of rumen flora that are positively correlated with semen quality. Overall, results indicate that feeding bulls corn silage as the primary source of forage could negatively impact semen quality and may not be appropriate as the primary roughage of forage for breeding bulls.

Calcium anacardate and its association with citric acid in diets for meat-type breeding quails.

The purpose of this study was to evaluate the effects of using calcium anacardate (CaA) as a source of anacardic acid and its association with citric acid (CA) in diets for breeding quails on the performance, the egg quality, incubation parameters, and progeny performance. Were used 540 quails European quails (Coturnix coturnix coturnix) that were 21 weeks old, housed in laying cages based on a completely randomized design, with nine treatments and six replications of 10 quails per parcel, with each experimental unit having eight females and two males. The following additions to the diet were evaluated: 1, no addition (control diet); 2, 0.25% CaA; 3, 0.25% CaA and 0.25% CA; 4, 0.50% CaA; 5, 0.50% CaA and 0.25% CA; 6, 0.50% CaA and 0.50% CA; 7, 0.75% CaA; 8, 0.75% CaA and 0.25% CA; and 9, 0.75% CaA and 0.50% CA. The treatments had no significant effects on the performance of the breeding quails, incubation parameters, and progeny performance. For egg quality, there was only an effect on yolk lipid oxidation, which was lower for eggs from quails fed the diets containing 0.50% CaA and 0.25% CA, 0.50% CaA and 0.50% CA, or 0.75% CaA alone, when compared with the control group. Considering that including CaA with or without CA in diets for breeding quails only affected yolk lipid oxidation, it can be recommend including 0.50% CaA and 0.25% CA or 0.75% CaA alone to mitigate oxidative damage in the yolk of fertile eggs.

Revelation of genes associated with energy generating metabolic pathways in the fighter type Aseel chicken of India through skeletal muscle transcriptome sequencing

In this study, comparative analysis of skeletal muscle transcriptome was carried out for four biological replicates of Aseel, a fighter type breed and Punjab Brown, a meat type breed of India. The profusely expressed genes in both breeds were related to muscle contraction and motor activity. Differential expression analysis identified 961 up-regulated and 979 down-regulated genes in Aseel at a threshold of log2 fold change ≥ ±2.0 (p adj<0.05). Significantly enriched KEGG pathways in Aseel included metabolic pathways and oxidative phosphorylation, with higher expression of genes associated with fatty acid beta-oxidation, formation of ATP by chemiosmotic coupling, response to oxidative stress, and muscle contraction. The highly connected hub genes identified through gene network analysis in the Aseel gamecocks were HNF4A, APOA2, APOB, APOC3, AMBP, and ACOT13, which are primarily associated with energy generating metabolic pathways. The up-regulated genes in Punjab Brown chicken were found to be related to muscle growth and differentiation. There was enrichment of pathways such as focal adhesion, insulin signaling pathway and ECM receptor interaction in these birds. The results presented in this study help to improve our understanding of the molecular mechanisms associated with fighting ability and muscle growth in Aseel and Punjab Brown chicken, respectively.

Occurrence of thermophilic Campylobacter spp. in chicken meat breeds from an organised farm in Thrissur district

Campylobacteriosis is one of the principal causes of gastroenteritis in the world. Poultry, being the natural reservoir, can harbour large number of Campylobacter in their caeca. The current study was carried out to assess the occurrence of thermophilic Campylobacter spp. in different meat type breeds in an organised farm. Out of the 120 cloacal swabs analysed, 31.67 per cent were found to be positive for Campylobacter spp. There was no significant difference in occurrence of Campylobacter spp. between different meat breeds. On molecular confirmation, majority of the isolates (71.05 per cent) were identified as Campylobacter jejuni and the rest as Campylobacter coli (28.95 per cent). The present study confirms a substantial degree of Campylobacter contamination in meat type chicken breeds in the farm. Good hygienic practices with better biosecurity measures and periodic screening of live poultry, poultry meat and its products are necessary to reduce the foodborne transmission of this pathogen to ensure safer food for consumers.

Conditions of southern Ukraine pigs productivity under different methods of breeding in modern

The article presents the results of studies concerning pigs’ productivity for purebred breeding and innovative approaches to crossbreeding schemes in the South of Ukraine. In general, sows of all experimental groups had high productivity both in purebred breeding and because of combining different forms with each other however there was no heterosis effect on the sows’ multiplicity in crossbreeding of Large White breed and the complexity of combining the sows of hybrid origin. Young hybrid animals of experimental groups reached a live weight of 100 kg sooner for 2.6-16.4 days or 1.4-8.9 % and feed costs were lower 0.12-0.34 feed units or 3.4-9.7 % per 1 kg gain during the fattening period.&#x0D; The obtained results show that the proposed production of final hybrids with a conditional proportion of blood landrace Ч large white in terms of live weight is the most successful and adapted to the technology of moderate intensity. The use of purebred and local animals related to the so-called "White breeds" - Large White and Landrace, is characterized by increased intensity of formation and indices of growth stress. The obtained results additionally confirm the complexity of adaptation of non-ferrous breeds (Duroc and especially Pietrain breeds) to the technological conditions of domestic pork farms. Young pigs were obtained in combinations where the parental form was the breed: Large White, Landrace or Duroc had the best exterior features that characterize the development of animals in length. In combinations where the parent form was the Pietrain breed, the latitudinal measurements and the meat index were improved against the background of a decrease in body length.&#x0D; A morphological study of carcasses of young pig stock of different origin has proved that implementation of up-to-date crossbreeding schemes with the use of meat-type breeds as paternal lines results in improved carcass dressing percentage and optimised lean-to-fat ratio. As evident out of the physical and chemical analysis of pork obtained from pigs of different breed-of-origin, all investigated parameters are within the current physiological limits. Most parameters have shown no significant difference, though tended to exhibit some peculiarities associated with the impact of genotype on the manifestation of one or another physical or chemical characteristic. The use of Pietrain breed as a sire line results in decreased intramuscular fat content, and hence the energy value of pork, with the back fat having the highest melting point which is indicative of its enhanced storability, though slightly impaired cooking properties as compared to similar products obtained from the offspring of the Large White and Landrace parents. With respect to its pH level and water-holding capacity, the pork from Pietrain-sired offspring is quite similar to PSE (Pale, Soft, Exudative) meat being slightly less tender and paler in colour and exhibiting greater weight loss during thermal processing. Also, a comprehensive sensory evaluation of boiled pork and pork broth obtained from a group of the Pietrain-sired young stock has got the lowest score, which is consistent with most of the physical and chemical properties of pork from pigs of this genotype; therefore, it is 75% purebred Landrace that should be favoured as a terminal sire line in crossbreeding programmes in order to obtain pork and bacon of improved quality in intensive commercial swine production systems. It is recommended to preliminary combine Pietrain and Duroc lines to produce terminal sires (Pietrain Ч Duroc) which will be further mated with two-breed-cross dams (LW Ч L).

Data evaluation of broiler chicken rearing and slaughter-An exploratory study.

To process and evaluate the data from broiler fattening and slaughtering, we investigated the production data of 107 straight run flocks of the commercial meat-type breed Ross 308 (Aviagen, EU). All flocks were raised and slaughtered in Germany and the average slaughter age was 37 days. The health outcomes of interest were mortality, average weight, and the slaughter results. First-week mortality, cumulative mortality, stocking density, flock size, season, production week of the parental flock, farm, antibiotic treatment, and the interaction between antibiotic treatment and season were considered as possible influencing factors. The average first-week mortality (FWM) and cumulative mortality percentages were 0.66 and 2.74%, respectively. First-week mortality was influenced by flock size, production week of the parental flock, and the interaction between antibiotic treatment and season, whereas cumulative mortality was influenced by antibiotic treatment, farm, and first-week mortality. The average weight (mean 2.30 kg) was influenced by season, stocking density, flock size, farm, and the interaction between antibiotic treatment and season. The condemnation rate was on average 1.48%, with the most common causes being deep dermatitis (mean 0.63%), ascites (mean 0.53%), and not suitable for production/general disease (mean 0.25%). Several factors influenced the causes of condemnation, with season being the most predominant one, followed by the interaction between antibiotic treatment and season, the antibiotic treatment alone, and stocking density.

Hereditary Basis of Coat Color and Excellent Feed Conversion Rate of Red Angus Cattle by Next-Generation Sequencing Data.

Simple SummaryThis study identified several variants and candidates with strong associations to coat color in Angus cattle by using genome sequencing data. In particular, the MC1R variants, which are a truncated MC1R protein obtained by altering the MCIR coding sequence region, result in lighter coat color and further enrich the genetic basis between DNA damage and melanin production caused. This study not only helped understand the hereditary basis of different coat colors, but also provided new ideas for future research on meat phenotypes. However, the putative candidate genes or markers identified in this study require further investigation to confirm their phenotypic causality and potential effective genetic relationships.Angus cattle have made remarkable contributions to the livestock industry worldwide as a commercial meat-type breed. Some evidence supported that Angus cattle with different coat colors have different feed-to-meat ratios, and the genetic basis of their coat color is inconclusive. Here, genome-wide association study was performed to investigate the genetic divergence of black and red Angus cattle with 63 public genome sequencing data. General linear model analysis was used to identify genomic regions with potential candidate variant/genes that contribute to coat color and feed conversion rate. Results showed that six single nucleotide polymorphisms (SNPs) and two insertion–deletions, which were annotated in five genes (ZCCHC14, ANKRD11, FANCA, MC1R, and LOC532875 [AFG3-like protein 1]), considerably diverged between black and red Angus cattle. The strongest associated loci, namely, missense mutation CHIR18_14705671 (c.296T > C) and frameshift mutation CHIR18_12999497 (c.310G>-), were located in MC1R. Three consecutive strongly associated SNPs were also identified and located in FANCA, which is widely involved in the Fanconi anemia pathway. Several SNPs of highly associated SNPs was notably enriched in ZCCHC14 and ANKRD11, which are related to myofiber growth and muscle development. This study provides a basis for the use of potential genetic markers to be used in future breeding programs to improve cattle selection in terms of coat color and meat phenotype. This study is also helpful to understand the hereditary basis of different coat colors and meat phenotypes. However, the putative candidate genes or markers identified in this study require further investigation to confirm their phenotypic causality and potential effective genetic relationships.

Genetic parameters of growth traits, trend of production and reproduction traits, and meat quality status of Ghagus, an indigenous chicken of India.

Indigenous chickens play a vital role in providing nutritional security and economic support for the rural and tribal people in tropical countries like India. Ghagus, an indigenous chicken breed of India, was characterized for growth, production, and reproduction (fertility and hatchability) traits over different generations and for carcass and meat quality traits. Heritability, and genetic and phenotypic correlations among growth traits were estimated using mixed model least squares and maximum likelihood methods. Estimates of heritability of growth traits such as bodyweights at different age and 8-week shank length were high (0.32 to 0.39) in initial generation and moderate to high during latest generation (0.20 to 0.42). The correlations of growth traits with 40-week egg production were positive and significant (P < 0.001). There was improvement in 8-week bodyweight (559.3 ± 4.40g) by 177g over the generations. The average egg production up to 40weeks over the generations was 35.66 eggs. There was also a significant (P < 0.001) increase in egg weights over the generations. The fertility (mean 89.3%) ranged from 85.2 to 92.3%. The hatchability on fertile egg set (mean 90.8%) ranged from 86.5 to 94.1% and it was improved by 3.9% over the generations. The carcass and meat quality study revealed that this breed has the lean meat, high protein, and attractive meat color with desirable meat quality characteristics. The study concluded that the Ghagus breed with self-propagation capacity has the potential to be improved as an indigenous meat-type breed to meet the ever-increasing demand for indigenous chickens' meat in the country.

Genome-wide association study and genomic heritabilities for blood protein levels in Lori-Bakhtiari sheep

Serum protein levels are related to physiological and pathological status of animals and could be affected by both genetic and environmental factors. This study aimed to evaluate genetic variation of serum protein profile in sheep. Blood samples were randomly collected from 96 Lori-Bakhtiari ewes, a heavy meat-type breed. Total protein, albumin, globulin, α1, α2, β and γ globulins and IgG levels were measured in blood serum. The samples were genotyped using the Illumina OvineSNP50 BeadChip. The studied traits adjusted for age, birth type, birth season and estimate of breeding value for body weight were considered as pseudo-phenotypes in genome-wide association analysis. In the GWAS model, the first five principal components were fitted as covariates to correct the biases due to possible population stratification. The Plink, R and GCTA software were used for genome-wide association analysis, construction of Q-Q and Manhattan plots and estimation of genetic variances, respectively. Noticeable genomic heritabilities ± SE were estimated for total and γ globulins (0.868 ± 0.262 and 0.831 ± 0.364, respectively), but other protein fractions had zero or close to zero estimates. Based on the Bonferroni adjusted p values, four QTLs located on 181.7 Mbp of OAR3, 107.7 Mbp of OAR4, 86.3 Mbp of OAR7 and 83.0 Mbp of OAR8 were significantly associated with α1, β, β and γ globulins, respectively. The results showed that the PKP2, IGF2R, SLC22A1 and SLC22A2 genes could be considered as candidate genes for blood serum proteins. The present study showed significant genetic variations of some blood protein fractions.

Whole-genome resequencing reveals genetic characteristics of different duck breeds from the Guangxi region in China

Distinctive indigenous duck (Anas platyrhynchos) populations of Guangxi, China, evolved due to the geographical, cultural, and environmental variability of this region. To investigate the genetic diversity and population structure of the indigenous ducks of Guangxi, 78 individuals from eight populations were collected and sequenced by whole-genome resequencing with an average depth of ∼9.40×. The eight indigenous duck populations included four breeds and four resource populations. Moreover, the genome data of 47 individuals from two typical meat-type breeds and two native egg-type breeds were obtained from a public database. Calculation of heterozygosity, nucleotide diversity (π), Tajima’s D, and FST indicated that the Guangxi populations were characterized by higher genetic diversity and lower differentiation than meat-type breeds. The highest diversity was observed in the Xilin-Ma ducks. Principal component, structure, and phylogenetic tree analyses revealed the relationship between the indigenous duck populations of Guangxi. A mild degree of differentiation was observed among the Guangxi populations, although three populations were closer to the meat or egg breeds. Indigenous populations are famous for their special flavor, small body size, and slow growth rates. Selective sweep analysis revealed the candidate genes and pathways associated with these growth traits. Our findings provide a valuable source of information regarding genetic diversity, population conservation, and genome-associated breeding of ducks.

Genetic Diversity of South African Indigenous Goat Population from Four Provinces Using Genome-Wide SNP Data

Genome-wide assessments of the genetic landscape of Farm Animal Genetic Resources (FAnGR) are key to developing sustainable breed improvements. Understanding the FAnGR adaptation to different environments and supporting their conservation programs from community initiative to national policymakers is very important. The objective of the study was to investigate the genetic diversity and population structure of communal indigenous goat populations from four provinces of South Africa. Communal indigenous goat populations from the Free State (FS) (n = 24), Gauteng (GP) (n = 28), Limpopo (LP) (n = 30), and North West (NW) (n = 35) provinces were genotyped using the Illumina Goats SNP50 BeadChip. An Illumina Goats SNP50 BeadChip data from commercial meat-type breeds: Boer (n = 33), Kalahari Red (n = 40), and Savanna (n = 31) was used in this study as reference populations. The Ho revealed that the genetic diversity of a population ranged between 0.39 ± 0.11 Ho in LP to 0.42 ± 0.09 Ho in NW. Analysis of molecular variance revealed variations of 3.39% (p &lt; 0.0001) and 90.64% among and within populations, respectively. The first two Principal Component Analyses (PCAs) revealed a unique Limpopo population separated from GP, FS, and NW communal indigenous goat populations with high levels of admixture with commercial goat populations. There were unique populations of Kalahari and Savanna that were observed and admixed individuals. Marker FST (Limpopo versus commercial goat populations) revealed 442 outlier single nucleotide polymorphisms (SNPs) across all chromosomes, and the SNP with the highest FST value (FST = 0.72; chromosome 8) was located on the UHRF2 gene. Population differentiation tests (PCAdapt) revealed PC2 as optimal and five outlier SNPs were detected on chromosomes 10, 15, 20, and 21. The study revealed that the SNPs identified by the first two principal components show high FST values in LP communal goat populations and allowed us to identify candidate genes which can be used in the development of breed selection programs to improve this unique LP population and other communal goat population of FS, GP, and NW, and find genetic factors contributing to the adaptation to harsh environments. Effective management and utilization of South African communal indigenous goat populations is important, and effort should be made to maintain unique genetic resources for conservation.

Genome-Wide Association Study of Weaning Traits in Lori-Bakhtiari Sheep

Abstract Weaning traits, including preweaning daily gain (PWDG) and weaning weight (WW) are important economic traits, especially for meat type mammals, with high impacts on growth performance and survival rate in higher ages. This study was conducted to perform a genome-wide association study (GWAS) on weaning traits in a meat type breed of sheep. Body weight records of 7557 Lori-Bakhtiari sheep with PWDG and WW records were used to estimate breeding values (EBVs) using an animal mixed model. A total of 132 animals were selected by two-tailed selection strategy, based on EBVs for body weight and then were genotyped using Illumina 50k Ovine SNP chip. After quality control, a total of 130 animals and 41323 SNPs were remained for further analyses. De-regressed estimates of breeding values were used as a pseudo-phenotype in GWAS analysis. Based on Bonferroni-adjusted p-values, five SNPs, located on chromosomes 2, 3, 4, 12 and 22 were significantly (p &lt; 0.05) associated with weaning traits and accounted for 5.06% and 0.37% of total genetic variations of PWDG and WW, respectively. Two SNPs on chromosomes 2 and 3 were located near to previously reported QTLs for weaning traits. Three genes, including ANGPTL7, mTOR and WDR11, were found within 50 kbp distances from the significant SNPs and thus could be considered as candidate genes for weaning traits. The detected QTLs and candidate genes could be studied for construction of breeding programs for genetic improvement of growth performance in meat type sheep.

Fatty Acid Composition and Regulatory Gene Expression in Late-Term Embryos of ACRB and COBB Broilers.

Cobb broilers (COBB) have been heavily selected for their production performance in the past several decades, while the Athens Canadian Random Bred (ACRB) chickens, a meat-type breed, have been kept as a non-selected control strain. The purpose of this study was to compare these two lines of chickens at late embryonic development and identify the molecular markers and fatty acid profiles underlining their differences in growth performance due to selection. Fertilized eggs of the ACRB (n = 6) and COBB (n = 6) were used at 14 and 18 embryonic days. Genes involved in lipogenesis and myogenesis were measured using quantitative real-time reverse transcroption-polymerase chain reaction (RT-PCR), and fatty acid (FA) compositions of egg yolk, muscle, and liver were measured using gas chromatography. COBB had higher egg weight, embryo weight, and breast and fat ratio. The gene expression in the liver showed an interaction between age and breed on FASN expression, with the highest level in COBB at E18. ACRB had higher ApoB and MTTP expression, but lower SREBP-1 expression compared to COBB. No difference was found in myogenesis gene expression in the muscle between two breeds. For the FA composition, muscle was largely affected by both breed and age. Yolk and liver were affected mainly by breed and age, respectively. Constant interaction effects in docosahexaenoic acid (DHA), indicating the highest level in all the tested tissues of ACRB at E14 and the constant main effects with higher myristic, palmitic, and gondoic, but lower linolenic acid in the liver and yolk of COBB compared to the levels in those of ACRB. Finally, fat accumulation in the liver had no obvious difference between the breeds but was higher when embryo was older. In conclusion, broiler breed affects egg, embryo, and tissue weight, as well as FA composition in initial egg yolk and throughout the embryonic development. The highest docosahexaenoic percentage was observed in ACRB, indicating that genetic selection may result in fatty acid profile changes such as lower DHA content in chicken tissues and eggs.

ASSESSMENT OF THE QUALITY OF MODERN COMMERCIAL PORK PRODUCTS

By a morphological study of carcasses of young pig stock of different origin, it has been proved that up-to-date crossbreeding schemes using meat-type breeds as parents increase the percentage of meat in a carcass and optimise the lean-to-fat ratio. Physicochemical analysis of pork obtained from pigs of different breeds has shown that all the parameters investigated are within the current physiological standards. Most parameters have shown no significant difference, though tend to exhibit some peculiarities associated with the effect of a genotype on how this or that physicochemical characteristic manifests itself. The use of the Piétrain breed as the sire line decreases the intramuscular fat content, and hence the calorific value of pork. The back fat of this breed has the highest melting point, which indicates its high storability, but somewhat lower cooking properties than those of similar products obtained from offspring of Large White and Landrace parents. The pH and water-holding capacity of the pork of Piétrain-sired offspring make it quite similar to PSE (Pale, Soft, Exudative) meat: this pork is slightly less tender and paler in colour and exhibits greater weight loss during thermal processing. Also, the result of a comprehensive sensory evaluation of boiled pork and pork broth obtained from Piétrain-sired young stock was the lowest, which is consistent with most of the physicochemical properties of pork from pigs of this genotype. So, it is the 75% purebred Landrace that should be favoured as a terminal sire line in crossbreeding programmes in order to obtain pork and bacon of improved quality in intensive commercial swine production systems. It is recommended to combine Piétrain and Duroc lines to produce terminal sires, ½ (Piétrain + Duroc), that will be further mated with two-breed-cross dams – ½ (Large White + Landrace).

Precision finishing of South African lambs in feedlots: a review.

In the intensification of sheep production systems, feedlot finishing plays a fundamental role in preparing lambs for slaughter, as well as relieving the grazing pressure on pasture. The profit margins in feedlot operations are often narrow and require the economics of scale to generate a sufficient income. In order to minimise expenses, intensive management and precision rearing of lambs to an ideal slaughter weight is needed to obtain premium carcass prices. The South African sheep industry is made up of wool, dual-purpose as well as meat type breeds, which also vary in terms of maturity. In order to implement precision finishing of South African lamb, a complete understanding of the growth, intake and fat deposition trends of growing lambs of different breed types is needed. This review outlines feedlot lamb production within the Southern African context for the major commercial breeds, while also providing insight in the considerations necessary to develop a decision support system for lamb rearing. Integrating such a decision support system into a lamb feedlot operation can then be used for precision finishing of lambs by predicting the optimal length of the feeding period and ideal slaughter weights of lambs.

Еconomic efficiency of local, merino and meat-type sheep breeds raised in Bulgaria without milking

Abstract. The goal of the present study is to perform an economic assessment of the local (autochthonic), merino and meat-type sheep breeds raised in Bulgaria without milking and under the conditions of a market economy and free commerce. We studied sheep from three herds, of the Srednostaroplaninska breed, Northeast Bulgarian Merino breed (NEBM) and the Île-de-France breed. The sheep from all three herds were under selection control. The results of the study indicated low economic effects for all three herds. Without subsidies, the local and merino breeds finished with negative values for profits and cost-efficiency of the income and expenses, and zero for the meat-types. The subsidy for the sheep of the Srednostaroplaninska breed made up 37.9% of the income, whereas the sold lambs and sheep culled for meat made up 60.7%. This indicated that the local mountain sheep cannot provide the necessary income for a farm’s normal function without milking and without subsidies, under the present market situation. The efforts in this field should be directed towards organic production of meat and dairy products and a closed production cycle. The income from sold lambs and sheep culled for meat from the NEBM breed made up 66.8% of the total income, whereas wool accounted for merely 4.6%. The subsidy provided 28.5% of the farm’s funds. Accomplishing an economic effect in merino breeds is possible only if prices for buying off wool were normalized, and the fertility of the ewes was increased. For the meat-type sheep of the Île-de-France breed, the income from selling meat and breeder lambs, as well as sold culled sheep made up 75.6%, and the subsidy – 22.7%. A higher economic effect for this breed could be achieved through selection towards fertility and more frequent births, i.e. 3 litters in 2 years. A significant productive and economic effect in the meat-type breeds could be achieved from ram breeding and conducting industrial crossbreeding in the stock part of the breeds.