The poultry industry is continuously seeking strategies to improve chicken health, welfare, and productivity while minimizing the use of antibiotics. Probiotics, as a natural alternative, have gained considerable attention due to their ability to modulate the gut microbiota, enhance immune function, and improve productive performance. The aim of this article is to provide updated information on the importance of probiotics in chicken. To achieve this, a systematic review was conducted to synthesize current findings on the impact of probiotics on chicken gut microbiota composition, immune responses, behavior, productive traits, and meat quality using literature databases such as PubMed, CABI Abstract, Google Scholar, and ScienceDirect from April 2010. The PRISMA method was adopted, where 85 articles met the criteria for this review article after several exclusion criteria. The review stated that due to the influence of the intestinal microbial balance, probiotics promote beneficial bacterial populations, suppress pathogens, improve gut health, and enhance nutrient absorption, improving growth performance. Additionally, the immunomodulatory effects of probiotics help strengthen the chicken’s immune system, reducing disease susceptibility. Moreover, recent studies suggest that probiotics may positively influence chicken behavior, particularly by reducing stress, enhancing overall health, and improving welfare conditions. This review also addresses gaps in knowledge, highlighting areas where further research is needed to optimize probiotic use in poultry production systems. Understanding both the short- and long-term effects of probiotics on chicken health and performance will provide critical insights for developing sustainable strategies to boost poultry industry outcomes.

The opportunities for sustainable utilisation and conservation of chicken genetic resources in Southern Africa need to be addressed. Indigenous chickens are an important animal genetic resource amongst resource-limited rural communities of Southern Africa. They play an important socio-economic role in traditional and religious ceremonies of rural households. They are important in customary rites, such as gift payments. Although the productivity of indigenous chickens in terms of growth and number of eggs per hen per year is low, its production is attained with minimal labour and rearing inputs. The low inputs and, consequently, low risk is one of the major advantages of indigenous chickens production. The conservation of these valuable chicken genetic resources is necessary in the light of the rapid loss of indigenous breeds and strains through commercial dilution and breed replacement. All varieties of domestic species and species with potential for domestication are considered to be important candidates for conservation. Indigenous chicken populations with economic potential, scientific use and cultural or aesthetic interest are of particular importance but all indigenous chickens which are unique and endangered should be incorporated into conservation efforts. This phenotypic information could be useful to standardise the different phenotypes within a region or country and design some criteria for characterisation and description of the indigenous chicken populations into breeds. Molecular markers are an indispensable tool to understand the genetic structures of populations. The assessed phenotypic coupled with genetic information could be a powerful tool towards the promotion of conservation and utilisation of indigenous chicken genetic resources.

Gastrointestinal parasitism, particularly nematode infection, is a major health issue affecting goats worldwide, resulting in clinical diseases and productivity loss. Prevalent gastrointestinal parasites (GIPs) affecting goats in South Africa are the Strongyloides papillosus, Eimeria spp., and Strongyles, especially the Haemonchus contortus and Trichostrongylus spp. According to the issues discussed in this paper and by other authors, the prevalence and intensity of various GIPs vary with an animal's location, breed, age, sex, and season. Because GIPs easily develop resistance to chemical treatment, selecting and breeding genetically GIP-resistant animals would be a relatively simple and inexpensive strategy for reducing or eliminating the current reliance on chemotherapy. Potential phenotypic indicators for selecting GIP-resistant goats include parasitological, immunological, and pathological phenotypic markers. Synergistic use of these indicators should be encouraged for a more accurate simplified genotype selection of resistant animals. Genes with Mendelian inheritance, particularly those involved in immunoregulatory mechanisms, have been identified in goats. Exploring this knowledge base to develop cost-effective molecular tools that facilitate enhanced genetic improvement programs is a current challenge. Future statistical and biological models should investigate genetic variations within genomic regions and different candidate genes involved in immunoregulatory mechanisms, as well as the identification of single nucleotide polymorphisms known to affect GIP infection levels.

The objectives of this study were to analyze the genetic diversity and structure of South African conserved and field chicken populations and to investigate the maternal lineages of these chicken populations. Four South African conserved chicken populations (n = 89), namely, Venda (VD_C), Ovambo, Naked Neck, and Potchefstroom Koekoek from the Animal Production Institute of the Agricultural Research Council, and 2 field populations, the Venda and Ovambo (OV_F), from which the Ovambo and the Venda conservation flocks were assumed to have been sampled, were genotyped for 460 bp of the mitochondrial DNA (mtDNA) D-loop sequence. Haplotypes of these chickens were aligned to 7 Japanese and 9 Chinese and Eurasian chicken mtDNA D-loop sequences taken from GenBank and reflecting populations from presumed centers of domestication. Sequence analysis revealed 48 polymorphic sites that defined 13 haplotypes in the South African chicken populations. All 6 South African conserved and field chicken populations observed were found to be polymorphic, with the number of haplotypes ranging from 3 for VD_C to 8 for OV_F. The lowest haplotype diversity, 0.54 ± 0.08, was observed in VD_C chickens, whereas the highest value, 0.88 ± 0.05, was observed in OV_F chickens. Genetic diversity between the 4 South African conserved and 2 field chicken populations constituted 12.34% of the total genetic variation, whereas within-population diversity constituted 87.66% of the total variation. The median network analysis of the mtDNA D-loop haplotypes observed in the South African conserved and field populations and the reference set resulted in 5 main clades. All 6 South African chickens were equally represented in the major clade, E, which is presumed to be of Indian subcontinent maternal origin and may have its roots in Southeast Asia. The results showed multiple maternal lineages of South African chickens. Conservation flocks and field chicken populations shared the major haplotypes A, D and E, which were presumed to be of Chinese, Southeast Asian, and Indian subcontinental origin.

The influence of stocking density on BW, egg weight (EW), and feed intake (FI) in Ross broiler breeder hens (n = 120) was investigated during the late medium egg production period (from 50 to 54 wk of age). Birds were randomly allocated to 6 pens in densities of 15, 20, and 25 birds/pen, giving rise to a floor space allowance of 5, 6.67, and 8.33 birds/m², respectively. Each density was replicated twice, and the order among the 6 pens was chosen at random. Data were analyzed using the repeated measures techniques of the Statistical Analysis System, considering the covariance structure of the observed data. There was a significant effect attributable to stocking density, time (in days), and their interaction for BW, EW, and FI. Birds in density of 6.67 per m² were lighter but had heavier eggs than birds in density of 5 per m²; however, birds in density of 8.33 per m² had similar BW and EW with birds in the other 2 groups. The mean FI were statistically different among the 3 groups, with a reduction in FI as density increases. Total egg production within the 3 density groups and average egg production per bird were also analyzed using categorical data techniques. The results indicated that stocking density influenced egg production, with birds at higher density producing fewer eggs per bird. Although generous floor space allowances were allocated per bird in this experiment, stocking density influenced the performance of broiler breeder hens.