Backyard poultry farming for sustained production and enhanced nutritional and livelihood security with special reference to India: a review

Comparative assessment of growth performance, heat resistance and carcass traits in four poultry genotypes reared in hot-humid tropical environment

This study investigated the impact of heat stress on growth and carcass traits in four poultry genotypes-Giriraja, Country chicken, Naked Neck and Kadaknath reared in a hot and humid tropical environment. Birds from all genotypes had ad libitum access to feed and water while being challenged with consistently high environmental temperatures in the experimental shed. Daily diurnal meteorological data were recorded inside and outside the shed. The study specifically examined growth variables and carcass characteristics. Significant differences (p < 0.01) were observed in body weight and average daily gain at various intervals. Notably, feed intake showed significant differences (p < 0.01) across weeks, indicating interactions between genotypes and time intervals. The feed conversion ratio (FCR) varied significantly (p < 0.01), with the highest FCR recorded in the Kadaknath breed. Livability percentages were similar across groups, except for Giriraja, which had significantly lower livability (p < 0.01). Carcass traits, including dressing, wings, feathers and giblet percentages, showed significant differences among genotypes (p < 0.01). Hepatic mRNA expression of growth-related genes revealed numerical variations, with Naked Neck displaying the highest (p < 0.05) fold change in IGF-1 expression compared to other genotypes. The study recognized in the Naked Neck genotype to possess higher resilience in maintaining homoeostasis and uncompromised growth under heat stress, providing valuable insights for sustainable poultry farming in challenging environmental conditions.

Backyard poultry: exploring non-intensive production systems

The concept of backyard poultry historically encompassed "food-producing animals." Nevertheless, a recent shift in livestock production paradigms within developed countries is evident, as backyard poultry owners now raise their birds for purposes beyond self-consumption, raising animals in a familiar way, and fostering emotional bonds with them. Because backyard animals are frequently privately owned, and the resulting products are typically not marketed, very little information is available about the demographic profile of backyard owners and information on flocks' characteristics, husbandry, and welfare. Thus, this review aims to clarify the characteristics of backyard poultry, highlighting the prevalent infectious diseases and the zoonotic risk to which farmers are exposed. According to the FAO, there are different types of poultry production systems: intensive, sub-intensive, and extensive. The system conditions, requirements, and the resulting performance differ extensively due to the type of breed, feeding practices, prevalence of disease, prevention and control of diseases, flock management, and the interactions among all these factors. The presence and transmission of infectious diseases in avian species is a problem that affects both the animals themselves and public health. Bacterial (Escherichia coli, Salmonella, Campylobacter, and Mycoplasma), parasitic (helminths, louses, and mites), and viral (Avian influenza, Newcastle, Marek, Infectious Bronchitis, Gumboro, Infectious Laringotracheitis, and Fowlpox) are the most important pathogens involved in backyard poultry health. In addition, Avian influenza, Salmonella, Campylobacter, and E. coli, could be a risk for backyard farmers and/or backyard-derived products consumers. Thus, proper biosecurity implementation measures are mandatory to control them. While the principles and practices of on-farm biosecurity may be well-versed among commercial farmers, hobbyists, and backyard farmers might not be familiar with the necessary steps to protect their flocks from infectious diseases and curb their transmission. This sector represents the fourth category of poultry farming, characterized by the lowest biosecurity standards. Consequently, it is imperative to address the legal status of backyard poultry, educate owners about biosecurity measures, and promote proper veterinary care and disease control.

Functional Quality Characteristics of the Meat from a Dual-Purpose Poultry Crossbreed Suitable for Backyard Rearing in Comparison to Commercial Broilers

Backyard poultry farming contributes to food security, nutrition, and the regular income of rural farmers in India. Their products have a niche market here and fetch higher prices than those of commercial poultry. Improved varieties are being developed to overcome the slow growth, late sexual maturity, and low production of indigenous breeds, while retaining their positive attributes. A comprehensive study was conducted to analyze the functional attributes of meat from the Jabalpur color (JBC), a colored, improved dual-purpose synthetic line, developed by Nanaji Deshmukh Veterinary Science University, Jabalpur, India. The birds were managed in a deep litter system under a backyard type of housing (night shelter and free range). Primal meat cuts (breast and thigh) of the male birds (n = 20/group) were evaluated at the age of marketing. The corresponding attributes were compared with the results obtained for commercial Cobb (400) broilers. The protein concentration of JBC breast (25.65 ± 0.39 g/100 g of tissue) and thigh (19.04 ± 0.23 g/100 g of tissue) meat was superior (p ≤ 0.05) to that of Cobb broilers. Established assays (in vitro) identified a better (p ≤ 0.05) antioxidation capacity in the JBC meat. High-performance liquid chromatography confirmed a considerable quantity of functional biomolecules (carnosine, anserine, and creatine) in the JBC breast and thigh meat extracts. The average carnosine concentration (mg/g of tissue) was 2.66 ± 0.09 and 1.11 ± 0.04 in the JBC breast and thigh meat, respectively. The mRNA expression was quantified by qRT-PCR for the carnosine-related genes: β-alanine transporter (SLC36A1), carnosine-synthesizing enzyme (CARNS1), and carnosine-degrading enzyme (CNDP2); this explained the comparable carnosine in the JBC and Cobb meat. Meat extracts from both genetic groups (JBC and Cobb) had high anti-glycation potential. Higher protein content and antioxidant capacity, along with the bioactive dipeptides in the JBC meat, herald exciting research opportunities for its use in improving the traditional backyard poultry farming system.

Study on the muscle transcriptome of two diverse Indian backyard poultry breeds acclimatized to different agro-ecological conditions

OBJECTIVE

Free-range (FR) poultry production systems are associated with quality products and improved welfare. All the 19 diverse chicken breeds of India have evolved under the FR system and are adapted to different agro-climatic conditions. It is vital to explore indigenous germplasm with modern genomic tools to have insights into genomic characteristics of production traits and adaptation.

METHODS

In this study, breast tissue transcriptome profiles were generated and analyzed from four biological replicates of two indigenous backyard poultry breeds of India-Ankaleshwar, a breed of the mainland, and Nicobari, a breed adapted to islands. The read quality of sequences was checked by FASTQC and processed reads were aligned to the reference genome (bGalGal1).

RESULTS

More than 94% mapping to the reference genome was observed for all samples. A total of 12,790 transcripts were common across both groups, while 657 were expressed only in Ankaleshwar and 169 in Nicobari. The highest expressed genes across both groups were associated mainly with muscle structure, contraction, and energy metabolism. The highly expressed genes identified in Ankaleshwar were involved in fatty acid catabolism and oxidative stress mitigation. Functional terms, pathways, and hub genes in Nicobari participated in muscle fiber growth, adipogenesis, and fatty acid anabolism. A key hub gene (RAC1) in Nicobari is a potential candidate affecting the laying rate in chickens. The qRT-PCR results also substantiate the RNA-seq results.

CONCLUSION

The findings provide a precious molecular resource to advance understanding of the genetic basis of adaptation, meat quality, and egg production in backyard chickens.

Genetic and phenotypic parameter estimates for selection within Ugandan indigenous chickens

The high genetic variation within indigenous chickens (IC) which provides an opportunity to select superior stock for sustainable production and conservation is under-exploited. This study is aimed at estimating heritability and genetic and phenotypic correlation coefficients of productive and reproductive traits of Ugandan IC as a basis for selection. Data on traits were collected across two consecutive generations, weight (W) and shank length (SL) of chicks at hatching (HW) as well as at 2 (W2; SL2), 4 (W4; SL4), 6 (W6; SL6), 8 (W8; SL8), and 12 (W12; SL12) weeks of growth. Body weights at onset of lay (WFE) were also measured. In addition, egg number (EN-60), egg weight (EW), clutch number (CLN-60), and clutch size (CLS-60) over a period of 60 days were recorded. Genetic parameters were estimated using the univariate animal model analysis with restricted maximum likelihood procedure using the variability package of R, version 4.1.1. Heritability of traits ranged from 0.30 and 0.72 except SL4 (0.02), SL12 (0.14), and EN-60 (0.17). The traits EN-60 and W4 were negatively phenotypically correlated (- 0.49). Body weight at first egg was highly genetically correlated (0.99) with SL8. Egg number was significantly, negatively, and genetically correlated (- 0.96) with SL12. In conclusion, shank length is a potential phenotypic marker when selecting for live weight at onset of lay and egg yield. The shank length could, therefore, permit selection of superior chickens at an early age.

Characterization of Mewari, an indigenous chicken breed, from hot tropical climate of India

Mewari, an indigenous chicken breed, was characterized for phenotypic parameters, growth, reproduction and production traits under the hot tropical climate of India. The data collected on 690 chicks were analyzed for effect of sex, hatch and their interaction on body weight and body measurements. The body weights of males were significantly higher at different weeks except at day old. Significantly higher shank and keel length was found in males as compared to females. The effect of hatch was significant on mean body weights at all ages, on shank length and breast angles at 8 weeks of age. The fertility and hatchability on fertile eggs set (FES) was 74.15±4.29% and 71.37±8.15%, respectively. The age at first egg (AFE) in the flock was 142 days and the age at sexual maturity (ASM) was 181.2±3.85 days. The average egg weights at 28 and 40 weks of age were 36.61±0.29 and 42.59±0.37 g, respectively. The hen day egg production (HDEP) up to 40 and 52 weeks of age was 28.93±0.13 and 59.87±0.14 eggs, respectively. The annual HDEP up to 72 weeks of age was 86.37± 0.13 eggs. The growth and egg production of Mewari chicken is comparable with other indigenous breeds. Mewari, a newly registered indigenous breed, needs to be further studied for various parameters to conserve and improve the breed for higher productivity.

Backyard poultry farming with improved germplasm: Sustainable food production and nutritional security in fragile ecosystem

Approximately 3 billion people were unable to afford a healthy diet in 2019 because of poverty and inequality. Most of these people live in Asia and Africa. Furthermore, 30% of the world population was affected by moderate to severe food insecurity in 2020, and most of this population lives in low- and middle-income countries. The world is at a critical juncture, and there is an urgent need for transformative food systems that ensure the empowerment of poor and vulnerable population groups, often smallholders with limited access to resources or those living in remote locations, as well as the empowerment of women, children, and youth (FAO, 2018). The backyard poultry production system (BPPS), as practiced by 80% of the world's rural population, can be that transformative change in low- and middle-income countries. Although the BPPS has low productivity, it still plays an important role in the food and nutritional security of rural people living in fragile ecosystems. Backyard poultry has been recognized as a tool for poverty alleviation and women empowerment besides ensuring food and nutritional security for rural poor. Poultry meat and eggs are the cheapest and best source of good quality protein, minerals, and vitamins. The introduction of improved backyard poultry germplasm has improved the productivity of this system in resource-poor settings and thereby improved the income and nutritional security of poor households. With these birds, the availability, access, utilization, and stability of food security have improved at household and national levels. Diseases, predation, non-availability of improved germplasm, lack of access to markets, and lack of skills are the major constraints to the adoption of improved backyard poultry. These constraints can be addressed by involving a network of community animal service providers. The improved backyard poultry germplasm will dominate the backyard poultry production system in the future and will be a tool for ensuring food and nutritional security on a sustainable basis, more particularly in low- and middle-income countries.

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 ± 4.40 g) by 177 g over the generations. The average egg production up to 40 weeks 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.

Domestication Explains Two-Thirds of Differential-Gene-Expression Variance between Domestic and Wild Animals; The Remaining One-Third Reflects Intraspecific and Interspecific Variation

Belyaev's concept of destabilizing selection during domestication was a major achievement in the XX century. Its practical value has been realized in commercial colors of the domesticated fox that never occur in the wild and has been confirmed in a wide variety of pet breeds. Many human disease models involving animals allow to test drugs before human testing. Perhaps this is why investigators doing transcriptomic profiling of domestic versus wild animals have searched for breed-specific patterns. Here we sequenced hypothalamic transcriptomes of tame and aggressive rats, identified their differentially expressed genes (DEGs), and, for the first time, applied principal component analysis to compare them with all the known DEGs of domestic versus wild animals that we could find. Two principal components, PC1 and PC2, respectively explained 67% and 33% of differential-gene-expression variance (hereinafter: log2 value) between domestic and wild animals. PC1 corresponded to multiple orthologous DEGs supported by homologs; these DEGs kept the log2 value sign from species to species and from tissue to tissue (i.e., a common domestication pattern). PC2 represented stand-alone homologous DEG pairs reversing the log2 value sign from one species to another and from tissue to tissue (i.e., representing intraspecific and interspecific variation).