The current research sought to assess the effects of paulownia leaves extract (PLE) on performance, blood hematological, antioxidant activity, and immunological response of broiler chicken. In total, two hundred 1-day-old male Cobb500 chicks were allocated randomly into four equal treatments with 5 replicates. The first treatment served as a control (CNT) and was fed the basal diet only, while the other treated treatments were fed on the basal diet supplemented with 0.1, 0.3, and 0.5 g/kg diet of PLE, respectively. The performance results showed significant increments (P < 0.05) in live body weight (LBW), weight gain (WG), and European production efficiency factors (EPEIs) (linearly; p < 0.001) in cooperated with increasing PLE levels in broiler diets. At the same time, feed conversion ratio (FCR) and livability percentages were numerically enhanced under the effects of PLE supplementation. Moreover, a notable increase (P < 0.05 or 0.01) in oxidative remarks activity (GSH, glutathione; SOD, super oxide-dismutase and CAT, catalase) and elevated levels of immunoglobulin (IgM, immunoglobulin M and IgG, immunoglobulin G) were noted (P < 0.05) for treatments fed with PLE in a dose-dependent manner. Also, a dramatic linear increase was observed in mRNA expression of IGF-1, GHR, IL-1β, and IL-10 genes of broiler chickens. This study concluded that enriched broiler feeds with 0.5 g/kg PLE might be a beneficial strategy to promote broiler health and production.

This study investigated the association between both polymorphisms and metabolic marker changes of the leptin gene, and body weight, weight gain, carcass traits, feed intake, and feed conversion ratio. Blood samples were collected from 60 V-line and 60 Baladi Black rabbits for DNA extraction and biochemical analysis. DNA sequencing of leptin (202-bp) revealed four non-synonymous single nucleotide polymorphism (SNPs) that characterized a number of V-line rabbits. Statistical analysis revealed that the identified SNPs were associated with rabbit growth and carcass measurements (p < 0.05). A discriminant analysis model showed a high classification percentage for the identified SNPs within and between breeds using body weight at 5-14 weeks of age (91.7%), slaughter traits (91.6%), feed intake, daily feed intake, and feed conversion ratio (76.7%). This study reveals that leptin gene could be a candidate for growth traits in rabbits enabling the development of marker-assisted selection (MAS) in different rabbit breeds.

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