Local Breeds Research Articles

Whole-genome resequencing identifies candidate genes associated with heat adaptation in chickens

The wide distribution and diverse varieties of chickens make them important models for studying genetic adaptation. The aim of this study was to identify genes that alter heat adaptation in commercial chicken breeds by comparing genetic differences between tropical and cold-resistant chickens. We analyzed whole-genome resequencing data of 186 chickens across various regions in Asia, including the following breeds: Bian chickens (B), Dagu chickens (DG), Beijing-You chickens (BY), and Gallus gallus jabouillei from China; Gallus gallus murghi from India; Vietnam native chickens (VN); Thailand native chickens (TN) and Gallus gallus spadiceus from Thailand; and Indonesia native chickens (IN), Gallus gallus gallus, and Gallus gallus bankiva from Indonesia. In total, 5,454,765 SNPs were identified for further analyses. Population genetic structure analysis revealed that each local chicken breed had undergone independent evolution. Additionally, when K = 5, B, BY, and DG chickens shared a common ancestor and exhibited high levels of inbreeding, suggesting that northern cold-resistant chickens are likely the result of artificial selection. In contrast, the runs of homozygosity (ROH) and the ROH-based genomic inbreeding coefficient (FROH) results for IN, TN, and VN chickens showed low levels of inbreeding. Low population differentiation index values indicated low differentiation levels, suggesting low genetic diversity in tropical chickens, implying increased vulnerability to environmental changes, decreased adaptability, and disease resistance. Whole-genome selection sweep analysis revealed 69 candidate genes, including LGR4, G6PC, and NBR1, between tropical and cold-resistant chickens. The genes were further subjected to GO and KEGG enrichment analyses, revealing that most of the genes were primarily enriched in biological synthesis processes, metabolic processes, central nervous system development, ion transmembrane transport, and the Wnt signaling pathway. Our study identified heat adaptation genes and their functions in chickens that primarily affect chickens in high-temperature environments through metabolic pathways. These heat-resistance genes provide a theoretical basis for improving the heat-adaptation capacity of commercial chicken breeds.

Effect of whole sesame seeds on the expression of key genes in monocytes of dairy goats

Whole sesame seeds (WSS) are good source of linoleic acid (LA) and lignans the effect of which have not been studied on the expression of key- genes in monocytes of dairy goats. Twenty-four, F2 crossbred [Alpine × Local (Greek) breeds] dairy goats (BW = 44.9 ± 5.4 kg), age (3–4 years old),were divided into three homogenous subgroups; the control group (CON) in which no WSS included and the two treated groups in the concentrates of which WSS were included at 5 % (WSS5) and 10 % (WSS10) respectively, by partially substituting both soybean meal and corn grain. The findings indicated a significant increase in the expression level of the IRF3 gene in the monocytes of goats fed with WSS5 compared to the CON group, throughout the experimental period. Both dietary inclusion levels of WSS caused a numerical downregulation in the expression levels of TNFA, IFNG, CCL5, and IL8. Additionally, the WSS10 group exhibited a numerical decrease in the expression levels of TLR4, IL1A, and IL1B compared to the other groups. Consequently, this study revealed that the inclusion of WSS in the above levels in goats’ diets does not modify pro-inflammatory signaling pathways or the expression patterns of genes. The lignans of WSS ensure the safe administration of their linoleic acid when these included at 5 % (WSS5) and 10 % (WSS10) of the concentrates in goats’ diets.

TRAINING ENVIRONMENT FOR RABBIT BUCKS: AN INTEGRAL REQUIREMENT IN ASSISTED REPRODUCTIVE TECHNOLOGY TOOL BOX

An experiment was conducted at the Abubakar Tafawa Balewa University Bauchi using 10 matured rabbit bucks with an average weight of 2.7kg which were 26weeks of age, 5each of exotic and local breeds. The bucks were managed in their cages for easy identification. The rabbits were fed ad- libitum. The trial was a 2*5 factorial design using 2 breeds and 5 replicates. The data generated were subjected to an analysis of variance (ANOVA). From the result, it was concluded that significant differences (P<0.05) between the semen harvested from the bucks in training crate and those from non-training crate or environment of previous trials in some of the seminal traits. Therefore, the use of training crates enriches the environment of the bucks and also increases convenience for the trainer to collect semen without difficulties. It is however, recommended that further study be conducted to elucidate this findings.

A mutation in POLR2A gene associated with body size traits in Dezhou donkeys revealed with GWAS.

The Dezhou donkey is a famous local donkey breed in China. The aim of the present study was to identify the genes associated with the body size traits of the Dezhou donkey and facilitate the breeding activities of the donkeys. A total of 349 donkeys from 2 generations (113 individuals in F0 and 236 in F1) were analyzed with restriction-site-associated DNA sequencing. A genome-wide association study revealed that the region between 13.7 and 15.6Mb of chromosome 13 is significantly associated with body sizes. Candidate genes related to body size development, including POLR2A, CHRNB1, FGF11, and ZBTB4, were identified. The results of GO and KEGG analysis indicated that the genes involved in many GO terms were related to metabolic processes and developmental processes. Additionally, a T>C mutation (Chr13:14312485) was found at intron 10 of the POLR2A gene. The association analysis showed significant differences among genotypes for the size traits. The body size of the individuals with the TT genotype was significantly higher than that with the CC genotype. The results showed that the polymorphism of POLR2A has the potential to be used as a marker in the breeding programs of the Dezhou donkeys.

Биологически ценные компоненты в сухих винах, изготовленных из винограда, культивируемого в Дагестане

Abstract. To expand the production of high-quality wines in Russia, it is necessary to use the varietal composition of grape raw materials, focusing on the indicators of the biochemical composition of local and introduced varieties, well adapted to the environmental conditions of terroirs. Viticulture is the leading branch of the agro-industrial complex of the Republic of Dagestan, which is one of the main producers of grapes and their processed products in the Russian Federation. The production of natural wines from local grape raw materials contributes to the growth of the economy and the prestige of Dagestan viticulture and winemaking. Therefore, the study of chemical parameters, including the vitamin composition and aroma-forming substances of experimental samples of dry white wines from grapes of introduced varieties Pervenets Magaracha, Rkatsiteli and varieties of local breeding Narma grown in Dagestan, is relevant. Standard research methods applied in enochemistry were used. The mass concentrations of vitamins and vitamin-like substances, phenolic compounds were determined using the capillary electrophoresis system "Kapel 104T", RF, NPF LUMEX, aroma-forming compounds – gas chromatograph "Crystal 2000M" (RF). Organoleptic ratings of Dagestan wines made in laboratory conditions – 7,5-7,8 points. Wine from the Narma variety excelled in the content of ascorbic acid – 18,93, orotic acid – 2,29 and coffee acid – 7,61 mg/dm3 . The highest total concentration of aromatic substances was determined in wine from the Pervenets Magaracha variety – 2178,30 mg/dm3 , and in wines from the Narma and Rkatsiteli varieties it was 743,29 and 777,81 mg/dm3 , respectively. Wine from Narma grapes has advantages in terms of the content of biologically active substances, and from the Pervenets of Magaracha – in terms of the number of aromatic compounds. Keywords: grapes, dry wine, vitamins, aroma-forming substances

Determinants of Adoption of Improved Sorghum Varieties by Small-Scale Farmers in Selected Districts of Western Oromia

Achieving national food security and diversifying export earnings from agricultural products is one of the major challenges currently facing developing countries like Ethiopia. Ethiopia is the largest producer of sorghum in Africa, contributing to ensuring food security in the country. Despite the high production potential and the economic importance of the crop, the adoption, and dissemination of improved sorghum varieties are constrained by various factors. To this end, this study aimed to identify determinants of adoption of improved sorghum varieties in selected districts of Western Oromia Region, Ethiopia with the specific objectives of identifying factors affecting adoption and assessing factors hindering the production of improved sorghum varieties. The study was based on cross-sectional data from 154 randomly selected sorghum-producing farmers. Descriptive and econometric analyses were used to analyze data. The results show that about 14.94% and 85.06% were adopters and non-adopters of the crop respectively. Probit model results showed that education and extension service affected the probability of adoption of improved sorghum varieties positively and significantly while TLU affected it negatively and significantly. Untimely availability of improved seed, Price of seed, Quality of improved seed, unavailability of credit to buy seed, Untimely availability of fertilizer, High price of fertilizer, Access to market information, Low grain price, and Pests and disease are the major constraints that affect sorghum production in the study area. This study suggests the high importance of institutional and government support in education, Extension service, and improved cows than a large number of local breeds. Therefore, policy and development interventions should give emphasis on the improvement of such institutional support systems so as to achieve the adoption practice which increases the production and productivity of small-scale farmers.

Cytogenetic study of Meriz goat breeds in Iraqi Kurdistan region.

Goats are considered the leading farm animal that has a substantial role in the agricultural sector in the Kurdistan Region of Iraq. No cytological examination has been carried out on them. This experiment aims to identify the Karyotype of the local breeds of domestic goats. This experiment was conducted on the Karyotype and prepared the ideogram of Meriz goats. The determination of the relative length and centromeric index arm ratio of the chromosomes in the breed was achieved by the production of karyotypes. A total of (30)Meriz goats, consisting of (10) males and (20) females, were selected to collect blood samples for a short-term lymphocyte culture. The diploid chromosome count was observed to be (60), consisting of (29) pairs of acrocentric autosomes and one pair of allosomes, specifically the X and Y chromosomes. The acrocentric nature of the X-chromosome and the sub-metacentric nature of the Y-chromosome were identified through scientific investigation. The study observed a variation in the relative length of autosomal chromosomes in Meriz goats, with females ranging from 4.49% to 1.89% and males ranging from (4.53%) to (1.75%). The X-chromosome had a relative length of 3.96 in females, while the Y-chromosome displayed a relative length of (5.05). The findings of this karyological investigation suggest that the chromosomal composition seen in the Meriz goats under examination was within the expected range of normalcy. It is recommended that more cytogenetic analyses be conducted at the population level in order to identify individuals within the Meriz breed population who possesses numerical and/or structural chromosome abnormalities. This research is crucial for enhancing the efficiency of production and reproduction in this breed.

In Vitro Gene Conservation Status and the Quality of the Genetic Resources of Native Hungarian Sheep Breeds.

Studies revealed a global loss of genetic resources for local sheep breeds. Therefore, the current study aimed to introduce and highlight the progress made on Hungary's existing gene conservation program (small Gene Bank). Furthermore, we evaluated breed (Tsigai, Cikta, and Racka), season, and individual variabilities (n = 24) of the pre-freeze and post-thaw semen stored in the Gene Bank to enhance the gene conservation of the breeds. The samples were cryopreserved manually, and post-thaw spermatozoa were analyzed for motility (CASA), viability, chromatin structure, and morphometry of the sperm nuclei. Ejaculate volume, spermatozoa concentration, subjective motility and standard motility, kinematic parameters, and spermatozoa's head area standard deviation of the post-thaw samples differed significantly among breeds (p < 0.05). Season affected ejaculate volume, total spermatozoa number/ejaculate, STR, BCF, and ALH. We observed a significant (p < 0.001; 0.05) breed and season interaction on concentration, total spermatozoa number/ejaculate, VCL, LIN, WOB, spermatozoa's head average perimeter and nucleus length (Tsigai and Cikta differed but were statistically the same as Racka). Similarly, season significantly (p < 0.05) affected the proportion of ejaculate suitable for freezing. There was a significant (p < 0.05) difference in kinematic parameters and viability among the rams across the breeds. The spermatozoa's head morphometry of the Tsigai and Cikta breeds differed significantly (p < 0.05) among the rams. There were individual and breed differences in many spermatozoa quality parameters. The stored samples are of good quality, with more than 40% having intact membranes and low abnormal chromatin condensation.

Seroprevalence of infectious bursal disease in backyard chickens of selected districts of Buno Bedelle zone, Southwestern Ethiopia.

Infectious bursal disease (IBD) is a viral infectious disease that affects young chicks. A cross-sectional study was conducted from October 2020 to June 2021 to determine seroprevalence and associated risk factors of IBD on backyard chickens of purposively selected three districts of Buno Bedelle Zone, Southwestern Ethiopia. The study was carried out via a collection of serum samples, questionnaire surveys, and a total of 768 serum samples were collected from randomly selected backyard chickens of the study areas and examined for the presence of IBD virus. These serum samples were processed by using an indirect enzyme-linked immunosorbent assay test procedure in laboratories. SPSS version 20 was used for data analysis and descriptive statics techniques were used. Out of a total serum samples collected, 361 of them were found positive for the disease with an overall seroprevalence of 47%. Different seroprevalence rates of IBD with 55.9%, 43.3% and 41.2% were recorded in Didessa, Chora and Gechi districts, respectively. The result indicated that there was statistically significant difference (p<0.05) of the disease among the three districts. Among the nine Peasant Associations (PAs) observed for seroprevalence of IBD, highest (62.9%) and lowest (34.20%) seroprevalence of the disease was recorded in Yembero and Shengela PAs, respectively. However, IBD was statistically significant in only Shengela PA of Chora district (p=0.04, OR=1.93 and 95% CI 1.04-3.58) and Seko PA of Gechi district (p=0.05, OR=1.79 and 95% CI 1.01-3.16). Even though sex, breed, age, source and management-based seroprevalence was observed in the present study, the result indicated that there was only statistical significant difference (p=0.004, OR=0.62 and 95% CI 0.45-0.86) seen in which higher seroprevalence of IBD was determined in exotic (50.3%) than in local (38.6%) chickens breeds of the study areas. Generally, higher seroprevalence of IBD in the present study indicates a widely distribution of the disease and one of the potential threats for poultry production in the study areas. So, chicken vaccination and improved management system should be warranted in order to control the disease effectively.

SEMEN CHARACTERISTICS OF THREE GENOTYPE OF INDIGENOUS COCKS IN THE HUMID ENVIRONMENT OF NIGERIA

The study was conducted to determine the semen characteristics of three genotypes of Nigerian Indigenous cocks. Thirty Six (60) local breeding cocks comprising of 20 frizzle, 20 normal and 20 naked neck selected randomly from the poultry breeding unit of the Ambrose Alli University Teaching and Research farm was used for this study. Semen were collected from them by abdominal massage and analyzed for semen characteristics. Semen concentration were significantly higher in normal 21.18±0.03mL (p&lt;0.05) than in frizzle feathered 20.19+0.093. and normal and naked neck feathered genotype 18.07±0.163. Sperm motility was significantly better (p&lt;0.05) in naked neck feather than in frizzle feather. Semen volume of the frizzle and normal feathered, were significantly higher (p&lt;0.05) than naked neck. Variations on semen characteristics abound in the three Nigerian indigenous cocks compared. Key words: Indigenous cocks, morphological defects, semen characteristics

THE EFFICACY OF TEASER BUCK INTRODUCTION AND HUMAN CHORIONIC GONADOTROPOHIN (HCG) IN THE INDUCTION OF OVULATION TO ENHANCE RECEPTIVITY AND FERTILITY IN RABBITS (Oryctolagus cunniculus) IN BAUCHI

This study was designed to evaluate the efficacy of teaser bucks introduction and human chorionic gonadotrophin (hCG) in the induction ovulation to enhance receptivity and conception rates in rabbits at the Teaching and Research farm of the Abubakar Tafawa Balawa University Bauchi. A total of (n=60) rabbit does and (n=10) male bucks were subjected into this trial. New Zealand white and their reciprocal crosses (n=30) and 30 local breeds, three stimulation protocols (hCG), teaser buck stimulation and natural method as control) were used. All the data generated were subjected to an analysis of variance. It was revealed that no significant differences (P&gt;0.05) were observed between breeds in receptivity for the treatments. However, Conception rates were significant (P&lt;0.05) in favour of the improved breeds and those treated with hCG. In conclusion, the use of teasers bucks, hCG based protocols during non-breeding season allows seasonal patterns of reproductive anoestrus to come on estrus, and allow receptivity and subsequently the insemination and pregnancy in rabbits that would otherwise be non-productive.

Characterization of Meat Metabolites and Lipids in Shanghai Local Pig Breeds Revealed by LC-MS-Based Method.

The meat of local livestock breeds often has unique qualities and flavors. In this study, three Shanghai native pig breeds (MSZ, SWT, and SHB) exhibited better meat quality traits than globalized commercial pig breeds (DLY). Subsequently, metabolomic and lipidomic differences in the longissimus dorsi (L) and gluteus (T) muscles of the Shanghai native pig breeds and DLY pig breed were compared using liquid chromatography-mass spectrometry (LC-MS). The results demonstrated that the metabolites mainly consisted of (28.16%) lipids and lipid-like molecules, and (25.87%) organic acids and their derivatives were the two most dominant groups. Hundreds of differential expression metabolites were identified in every compared group, respectively. One-way ANOVA was applied to test the significance between multiple groups. Among the 20 most abundant differential metabolites, L-carnitine was significantly different in the muscles of the four pig breeds (p-value = 7.322 × 10-11). It was significantly higher in the L and T muscles of the two indigenous black pig breeds (MSZ and SWT) than in the DLY pigs (p-value < 0.001). Similarly, lipidomic analysis revealed the PA (18:0/18:2) was significantly more abundant in the muscle of these two black breeds than that in the DLY breed (p-value < 0.001). These specific metabolites and lipids might influence the meat quality and taste properties and lead to customer preferences. Therefore, this study provided insights into the characterization of meat metabolites and lipids in Shanghai native pig breeds.

Socio-economic aspects and farming practices of goats in Southern Tunisia.

This study aims to describe socio-economic aspects, farming practices and production limitations of goats by surveying 53 farms holding 5507 head in the regions of Tataouine-Tunisia. It was revealed that goats represented a major source of income for most of the producers (66.1%). Approximately 35.8% of the farmers had not received formal education, with the majority (56.6%) having been engaged in goat breeding for over 10 years. Additionally, 50.9% of stockholders relied on technical knowledge for animal breeding. The investigated herds were mostly (97.4%) comprised of local goat breeds. The most common management system was semi-intensive (49.1%) based on grazing in communal rangelands and supplementation with agricultural by-products and concentrates. The fertility, fecundity and prolificacy rates were 91.3 ± 8.3, 109.8 ± 19.5 and 127.0 ± 15.4%, respectively. The main reasons for keeping goats were their major contribution to the income by the sale of male kids and the provision of milk for home consumption. Sale of male kids at an age of 7.7 months was practiced mostly via intermediaries (94.3%) and rarely directly to butchers and markets (5.7%). The total amount of milk produced on each farm was on average 15.1l/day, and more than half of farmers (54.7%) consumed goat milk as part of their daily diet. The majority (71.7%) of respondents locally processed milk into Leben, Rayeb and cheese because the goat milk market faced constraints in the Tataouine regions, mainly in terms insufficient milk production and low consumer acceptability. Goats contribute to the income source in rural zones of southern Tunisia, where their breeding is mainly for the purpose of meat sale and the provision of milk for home consumption. The development of goat milk market can represent an added value to this sector.

Optimal management plans and initiatives for the valorization and safeguarding of local breeds: a mathematical programming approach

In this study, a parametric programming model was developed in order to deliver optimal management plans for various types of farms rearing endangered Greek sheep breeds under three distinct scenarios. The first scenario investigated the optimal internal organization of farms (i.e., management practices and resource allocation strategies that increase profitability of farms) under current market conditions (e.g., product prices) without, however, considering subsidies and compensations. The second assessed the impact of an agri-environmental support scheme on farm optimal structure and socioeconomic performance. The third investigated the effects of integrating farms into value chains and niche markets where premium prices prevail. For this purpose, a questionnaire survey was conducted in the wider region of Epirus and Thessaly, collecting management data from 16 farms rearing (i) Kalaritiko, (ii) Orino Epiru and (iii) Katsika rare sheep breeds. The main finding of this study was that the optimal internal organization of farms is essential for their self-reliance and viability. Therefore, it should be the basis in the designing of any initiative aimed at the preservation and valorization of local breeds. Furthermore, the analysis showed that a niche marketing strategy (i.e., a premium price strategy) can have a broader positive impact on farms structure and socioeconomic performance, particularly those engaged in cheese production, compared to an agri-environmental scheme. However, due to the fact that both initiatives possess limitations that may render them inefficient under specific external conditions, the development of an integrated incentive mechanism, which will combine both policy schemes and market-based initiatives, appeared to be a more effective strategy for the long-term viability of farms.

Genomic Reference Resource for African Cattle: Genome Sequences and High-Density Array Variants

The diversity in genome resources is fundamental to designing genomic strategies for local breed improvement and utilisation. These resources also support gene discovery and enhance our understanding of the mechanisms of resilience with applications beyond local breeds. Here, we report the genome sequences of 555 cattle (208 of which comprise new data) and high-density (HD) array genotyping of 1,082 samples (537 new samples) from indigenous African cattle populations. The new sequences have an average genome coverage of ~30X, three times higher than the average (~10X) of the over 300 sequences already in the public domain. Following variant quality checks, we identified approximately 32.3 million sequence variants and 661,943 HD autosomal variants mapped to the Bos taurus reference genome (ARS-UCD1.2). The new datasets were generated as part of the Centre for Tropical Livestock Genetics and Health (CTLGH) Genomic Reference Resource for African Cattle (GRRFAC) initiative, which aspires to facilitate the generation of this livestock resource and hopes for its utilisation for complete indigenous breed characterisation and sustainable global livestock improvement.

Effect of genotype and nutritional and environmental challenges on growth curve dynamics of broiler chickens

The present study aimed to compare the dynamics of growth of various chicken genotypes exposed to heat stress, low-input diets, and free-range farming by using Gompertz model to gain insights into their capabilities to face environmental and nutritional challenges. Three in vivo trials (T1: heat stress, T2: low-input diets, and T3: free-range system) were conducted, involving a total of 671 animals. Five chicken genotypes were employed in each trial: 2 Italian local breeds, Bionda Piemontese (BP) and Robusta Maculata (RM), along with their crossbreeds with Sasso hens (BP×SA and RM×SA), and a commercial hybrid (Ross 308). One-day-old male chicks were individually identified, and the 5 genotypes were randomly allocated to different challenging conditions: T1 involved 2 environmental temperatures (thermoneutral vs. high temperature); T2 involved 2 diets (standard vs. low-input); T3 involved 2 rearing systems (conventional vs. free-range). The chickens were weighed once a week from their arrival until slaughtering, and the data were used to build growth curves using the Gompertz model. Chickens from different genotypes were slaughtered at varying ages based on their maturity. In all trials, the challenging conditions significantly reduced adult body weight (A; -31.0%) and maximum growth rate (MGR; -25.6%) of Ross chickens. In contrast, in T1 and T2, no significant changes were observed in the main growth curve parameters of local breeds and crossbreeds, while under free-range conditions, there was even an increase in the A and MGR of these genotypes. The crossbreeding was effective in increasing A and MGR of BP (+30.5% in BP×SA), as well as in improving the precocity and MGR of RM (+19.5% in RM×SA). Our findings highlight the effectiveness of the Gompertz model as a tool for evaluating birds' adaptability and confirm the greater ability of local breeds and crossbreeds to adapt to different challenges. In conclusion, our methodological approach could be used to choose the genotype most suited to the environmental context and confirm the potential advantages of crossbreeding for enhancing resilience and sustainability.

Screening of &lt;em&gt;FecLL&lt;/em&gt; prolific allele of the &lt;em&gt;B4GALNT2&lt;/em&gt; gene in Algerian sheep populations

Background: Research on the main genes controlling prolificacy in sheep, also known as fecundity genes (Fec genes), has highlighted the mechanisms involved in ewe fertility and the genetic improvement of prolificacy. The gene, FecL/B4GALNT2 (beta-1,4-N-acetyl-galactosaminyl transferase 2) and its prolific allele FecLL, which segregate in French Lacaune sheep and some local sheep breeds in Morocco and Tunisia, were found to influence ovarian function. However, their action differs from that of other major genes discovered previously, such as: FecX/BMP15 (bone morphogenetic protein 15); FecG/GDF9 (growth differentiation factor 9); and FecB/BMPR1B (bone morphogenetic protein receptor type 1B). The latter act in the bone morphogenetic protein (BMP) signalling pathway. Aim: The objective of this study is to investigate the segregation of the FecLL allele in Algerian sheep populations. Methods: A total of 338 animals from 12 breeds were genotyped using the PCR-RFLP technique. Results: Our results revealed the presence of FecLL in the Algerian D’man sheep population. Among the genotyped D’man sheep, 21% were carriers of the mutation in the heterozygous state. The frequency of the FecLL allele in the Algerian D’man population (0.11) is close to what is observed in Lacaune sheep and remains relatively low compared to Moroccan (0.58) and Tunisian (0.65) D’man sheep. Conclusions: The FecLL allele, which is shared by the French Lacaune population and the North African D’man populations, could indicate the ancestral origin of the mutation in B4GALNT2 or the occurrence of an ancient introgression event to improve prolificacy. Managing this mutation in Algerian D’man flocks could help improve the numerical productivity of D’man sheep in Algeria.

Research Note: Study on the in-situ preservation of pigeons based on the level of endangerment of genetic resources

The large-scale and intensive development of the meat pigeon breeding industry have resulted in the replacement of a large number of low-performance local breeds by a few breeds with excellent production performance. However, due to the characteristics of pigeon species that are monogamous, for which the W chromosome cannot be recovered and for which semen cannot be cryopreserved, the preservation of pigeon species is still mainly based on in-situ preservation. In this study, pigeons were classified into six classes of endangerment based on the criteria of the 100-year inbreeding coefficient of poultry populations in the “Assessment of Endangered Poultry Genetic Resources” (NY/T 2996-2016). The results show that when the generation interval was 1.5 years, the number of ideal populations with the same gene frequency variance or the same heterozygosity decay rate of pigeons in class 1 to 5 was ≤149, 150–204, 205–316, 317–649 and ≥650. In random-reserved breeding, when the generation interval was 1.5 years, the number of male (female) pigeons corresponding to class 1 to 5 was ≤74, 75–102, 103–157, 158–324 and ≥325. In family-equal-reserved breeding, when the generation interval was 1.5 years, the number of male (female) pigeons corresponding to class 1 to 5 was ≤36, 37–50, 51–78, 79–162 and ≥163. When the generation interval was 1.5 years, the inbreeding increments corresponding to class 1 to 5 were ≥0.00335, 0.00244–0.00334, 0.00159–0.00243, 0.00078–0.00158 and ≤0.00077; with the same population size, the inbreeding coefficient and inbreeding increment decreased with the increase of generation interval; the population effective content, inbreeding coefficient and inbreeding increment of family-equal-reserved pigeons were lower than those of random-reserved pigeons. The results of this study have certain reference value for analyzing the status quo of local and endangered species, constructing live gene banks and breeding farms of poultry genetic resources, and rescuing endangered species.

Whole-genome analysis reveals distinct adaptation signatures to diverse environments in Chinese domestic pigs

BackgroundLong-term natural and artificial selection has resulted in many genetic footprints within the genomes of pig breeds across distinct agroecological zones. Nevertheless, the mechanisms by which these signatures contribute to phenotypic diversity and facilitate environmental adaptation remain unclear.ResultsHere, we leveraged whole-genome sequencing data from 82 individuals from 6 domestic pig breeds originating in tropical, high-altitude, and frigid regions. Population genetic analysis suggested that habitat isolation significantly shaped the genetic diversity and contributed to population stratification in local Chinese pig breeds. Analysis of selection signals revealed regions under selection for adaptation in tropical (55.5 Mb), high-altitude (43.6 Mb), and frigid (17.72 Mb) regions. The potential functions of the selective sweep regions were linked to certain complex traits that might play critical roles in different geographic environments, including fat coverage in frigid environments and blood indicators in tropical and high-altitude environments. Candidate genes under selection were significantly enriched in biological pathways involved in environmental adaptation. These pathways included blood circulation, protein degradation, and inflammation for adaptation to tropical environments; heart and lung development, hypoxia response, and DNA damage repair for high-altitude adaptation; and thermogenesis, cold-induced vasodilation (CIVD), and the cell cycle for adaptation to frigid environments. By examining the chromatin state of the selection signatures, we identified the lung and ileum as two candidate functional tissues for environmental adaptation. Finally, we identified a mutation (chr1: G246,175,129A) in the cis-regulatory region of ABCA1 as a plausible promising variant for adaptation to tropical environments.ConclusionsIn this study, we conducted a genome-wide exploration of the genetic mechanisms underlying the adaptability of local Chinese pig breeds to tropical, high-altitude, and frigid environments. Our findings shed light on the prominent role of cis-regulatory elements in environmental adaptation in pigs and may serve as a valuable biological model of human plateau-related disorders and cardiovascular diseases.

Research Progress in the Establishment of Sterile Hosts and Their Usage in Conservation of Poultry Genetic Resources

Many local chicken breeds are rapidly declining and even facing extinction due to a variety of factors such as indiscriminate crossbreeding, climate fluctuations, epidemic outbreak, and environmental changes. Developing effective preservation strategies is important to address this situation. The special reproductive characteristics and gamete morphology of chickens pose challenges for preserving genetic heritage through the cryopreservation of genetic materials. Currently, gonad and primordial germ-cell cryopreservation and transplantation are the most promising approaches, especially for the genetic information in the W chromosome of female birds. The study of establishing sterile recipients is crucial for increasing the efficiency of the colonization of transplanted donor tissues and cells. Several classical methods, including ovariectomy and testectomy, busulfan, and irradiation, have been employed to deplete endogenous germ cells in recipient males before transplantation. These methods rely on the toxicity of chemical reagents and physical stimulation to kill germ cells. Recent advances in gene-editing technology have introduced sterile hosts via the knocking out of genes relevant to germ cells’ development. This review explores state-of-the-art technologies for preparing infertile avian recipients (mainly chickens) and aims to provide guidance for the conservation of poultry genetic material and breed restoration.