Alzahraa Abdelatty

Indigenous chicken breeds in developing countries have diverse benefits to rural economy as a source of high-quality animal protein. However, there are few reports on the evaluation of economic traits in Egyptian indigenous breeds. Hence, this study aimed to investigate growth performance, carcass characteristics, body measurements and meat quality traits in two indigenous breeds of chickens (Benha line and Golden Montazah) versus Rhode Island Red as a reference worldwide breed. Besides, a time series expression profile of somatotropic axis genes including GH and IGF-1 and their plasma level concentrations were investigated. Benha line chickens (BL) revealed the highest improved estimates of growth performance, carcass characteristics and meat quality traits. In the same manner, it displayed the highest levels of hepatic GH and IGF-1 and muscle IGF-1 gene expression compared to Rhode Island Red (RIR) and Golden Montazah (GM) chickens. Accordingly, BL exhibited the highest levels of plasma IGF-1 and the lowest levels of plasma GH. This result suggests the direct association between growth performance, carcass characteristics and levels of IGF-1 gene expression in the selected chicken breeds. BL is a superior Egyptian genotype with candidate productive traits and competing characteristics, it could be used widely as a proven ancestor of commercial hybrid breeds.

Fishmeal (FM) is the main protein source in fish feed. However, it is quite expensive due to its limited resources. Therefore, finding a dietary alternative to the FM to sustain fish production is crucial, and the current study was performed to assess the impact of poultry offal silage (POS) with or without betaine supplementation; as an effective and cheaper alternative to FM; on feed efficiency, growth performance, spleen morphology and intestinal morphometry of Nile tilapia (Oreochromis niloticus) fingerlings. Four dietary treatments were formulated: (1) FM based diet, (2) FM-B; FM diet +0.7% betaine, (3) POS diet and (4) POS-B; POS diet +0.7% betaine. Each dietary treatment consisted of three replicates (n = 10/replicate), and the experiment was continued for 16 weeks. By the end of the experiment, spleen and intestine specimens were collected from 15 fish (n = 5/replicate) for histopathological assessment. The results were statistically analysed using GLM procedures of SAS 9.4. Feed efficiency increased in both POS-B and FM-B groups (p = 0.01), while body weight and body weight gain showed only weak tendencies towards an increase (p = 0.10 and 0.12, respectively). The villi length was the highest in POS-B fed group (p < 0.01). In addition, melanomacrophage centres of the spleen increased in both betaine-supplemented groups (p < 0.01). From our findings, we conclude that betaine supplementation with poultry offal silage improved production performance and immune status of Nile tilapia fish.