Emmanuel Okoli Odah

Feed efficiency (FE) is a major determinant of economic and environmental sustainability in Atlantic salmon aquaculture, yet the biological drivers of FE during the saltwater (SW) phase remain poorly understood. This study aimed to develop and validate methods for predicting visceral fat percentage (VFP) and estimate its genetic relationships with growth, fillet lipid deposition, and feed-efficiency traits. A population of 836 fish from 30 families was phenotyped for growth, feed intake, and body composition traits. VFP was predicted with high accuracy using near-infrared spectroscopy on homogenized viscera (cross-validated R2 = 0.91), while fillet fat percentage (FFP) was predicted using Raman spectroscopy (cross-validated R2 = 0.58). Genetic parameters were estimated using animal models based on genomic relationships. VFP was moderately heritable (h2 = 0.28 ± 0.06) and showed a strong positive genetic correlation with feed conversion ratio (FCR; rg = 0.90), indicating that lower visceral lipid was genetically associated with improved FE. When relative visceral weight was partitioned into lipid and non-lipid components, decreased visceral lipid was specifically associated with improved FCR, whereas increased relative non-lipid organ visceral mass was associated with higher specific growth rate. FFP was only moderately genetically correlated with FCR traits (rg = 0.34-0.53). A negative partial genetic correlation between VFP and FFP conditional on body weight (rg = -0.36 ± 0.15) suggested a small allocation tradeoff between lipid compartments. Overall, visceral lipid content is a heritable and informative indicator trait for improving FE in SW Atlantic salmon.

Chicken production is an essential venture for steady household income generation, poverty alleviation and provision of quality nutritional aids. This study was conducted to compare growth performance of Kuroiler and Nigerian indigenous naked neck chickens reared in the tropics. A total of 538 birds comprising 345 indigenous Nigerian naked neck and 193 Kuroiler chickens genotypes were sampled. Body weight and linear body measurements were observed at 2, 4, 6, 8 and 10th week. Data obtained were subjected to 2-way analysis of variance using GLM procedure of SAS. There exist significant variations in chicken genotype with growth performance. Kuroiler birds significantly showed heavier mean body weight (p<0.05) at various critical growth stages observed than the Nigerian indigenous naked neck chickens reared under same conditions. The influence of genotype and sex on mean body weight and breast girth measures of chickens remain insignificant throughout early growth stages. However, at 6th, 8th and 10th week of age, Kuroiler breeds demonstrated superior growth rate and performance response compared to Nigerian indigenous naked neck fowls. Both chicken breeds exhibited differential growth patterns and sexual dimorphism in favour of male populations. Introduction and crossing of Kuroiler strains with Nigerian indigenous naked neck birds might result in better performance and adaptability.