Advanced Practical Strategies to Enhance Table Egg Production.

The global demand for table eggs has increased exponentially due to the growing human population. To meet this demand, major advances in hen genetics, nutrition, and husbandry procedures are required. Developing cost-effective and practically applicable strategies to improve egg production and quality is necessary for the development of egg industry worldwide. Consumers have shown a strong desire regarding the improvement of hens' welfare and egg quality. They also become interested in functional and designer foods. Modifications in the nutritional composition of laying hen diets significantly impact egg nutritional composition and quality preservation. According to previous scientific research, enriched egg products can benefit human health. However, producers are facing a serious challenge in optimizing breeding, housing, and dietary strategies to ensure hen health and high product quality. This review discussed several practical strategies to increase egg production, quality, and hens' welfare. These practical strategies can potentially be used in layer farms for sustainable egg production. One of these strategies is the transition from conventional to enriched or cage-free production systems, thereby improving bird behavior and welfare. In addition, widely use of plant/herbal substances as dietary supplements in layers' diets positively impacts hens' physiological, productive, reproductive, and immunological performances.

Some recent applications of rabbit biotechnology - a review.

The rabbit is gaining attention in the biotechnology field because it offers several advantages as a specific experimental model. Both wild and domestic rabbits exist. They are prey, browsers and ecosystem keystone species, and they also exhibit high production. Rabbit biotechnology is a branch of animal biotechnology in which molecular biology techniques are used to modify living organisms and make products. The advances in biotechnology have created new applications in rabbit genetics. These applications have moved from measuring the phenotype to assessing the genotype and are now based on the science of genetic engineering. The novel aspect introduced by biotechnology is the modification of gene sequences that influence the traits of interest. This review integrates recent developments in biotechnology that influence traits of interest in rabbits.

Association of Melanocortin (MC4R) and Myostatin (MSTN) genes with carcass quality in rabbit.

The aim of this study was to investigate the association of Melanocortin (MC4R) and Myostatin (MSTN) with the carcass quality of V-line and Alexandria line rabbits. MC4R and MSTN were screened by single-strand conformational polymorphism analysis (SSCP) then DNA was sequenced. The results identified four novel SNPs using the four studied primers of the MC4R and MSTN genes. The genotype (BB) has significant higher body weight (BW), carcass weight (CW) and dressing percentage (DP) than AA rabbits. There were no significant differences within the two lines in the carcass color (light pink) and carcass fat (CF). GLM analysis for the effect of genotypes on carcass traits demonstrated that the genotype (BB) was significantly associated with high carcass weight (CW) and dressing percentage (DP). The detected mutations and the analysis of carcass quality means revealed a significant association between MSTN and MC4R polymorphisms with some carcass traits that affect meat quality of rabbits.

Comparison of milk production and milk composition for an exotic and a local synthetic rabbit lines.

AIM: Basic objective of this research was to compare two rabbit lines: V-line (exotic line), Alexandria (local synthetic line) for yield and composition of milk product and their effect on productive performance of rabbits. MATERIALS AND METHODS: The experiment was conducted on 80 does and their kits. Milk yield (MY) of each doe and milk composition (MC) were recorded at 3rd week of lactation. RESULTS: The results of MY showed insignificant difference between V-line and Alexandria line. While the results of MC indicated significant differences in milk protein and fat between the two lines. The protein electrophoresis was used for assaying variation in milk proteins between the two lines. The banding protein patterns showed seven protein bands for Alexandria line and six bands for V line. The results demonstrated one specific protein marker at 48 KDa (κ-casein) in Alexandria doe's milk. Moreover, the results of individual body weight at weaning age indicated that Alexandria rabbits had significantly higher body weight compared with V-line rabbits (845.33 g, 664.05 g, respectively). Alexandria line had significantly lower mortality rate compared with V-line (1.5%, 2.7%, respectively). CONCLUSION: The differences which obtained in Alexandria line milk may play an important role in the productive performance of rabbits.

Associations between single nucleotide polymorphisms in multiple candidate genes and body weight in rabbits.

AIM: In this study, we examined parts of six growth genes (growth hormone [GH], melanocortin 4 receptor [MC4R], growth hormone receptor [GHR], phosphorglycerate mutase [PGAM], myostatin [MSTN], and fibroblast growth factor [FGF]) as specific primers for two rabbit lines (V-line, Alexandria) using nucleotide sequence analysis, to investigate association between detecting single nucleotide polymorphism (SNP) of these genes and body weight (BW) at market. MATERIALS AND METHODS: Each line kits were grouped into high and low weight rabbits to identify DNA markers useful for association studies with high BW. DNA from blood samples of each group was extracted to amplify the six growth genes. SNP technique was used to study the associate polymorphism in the six growth genes and marketing BW (at 63 days) in the two rabbit lines. The purified polymerase chain reaction products were sequenced in those had the highest and lowest BW in each line. RESULTS: Alignment of sequence data from each group revealed the following SNPs: At nucleotide 23 (A-C) and nucleotide 35 (T-G) in MC4R gene (sense mutation) of Alexandria and V-line high BW. Furthermore, we detected the following SNPs variation between the two lines: A SNP (T-C) at nucleotide 27 was identified by MC4R gene (sense mutation) and another one (A-C) at nucleotide 14 was identified by GHR gene (nonsense mutation) of Alexandria line. The results of individual BW at market (63 days) indicated that Alexandria rabbits had significantly higher BW compared with V-line rabbits. MC4R polymorphism showed significant association with high BW in rabbits. CONCLUSION: The results of polymorphism demonstrate the possibility to detect an association between BW in rabbits and the efficiency of the used primers to predict through the genetic specificity using the SNP of MC4R.