Transcriptomic and metabolomic analysis based on different aggressive pecking phenotype in duck.

Aggressive pecking is an important welfare and production efficiency issue in poultry farming. The precise mechanisms underlying the occurrence of aggressive pecking remain poorly understood. In this study, we selected Sansui ducks that performed aggressive pecking and ducks that did not perform aggressive pecking from video recordings. Transcriptomic and metabolomic analyses of the whole brains of aggressive pecking ducks and normal ducks revealed 504 differentially expressed genes and 5 differentially altered metabolites (adenosine, guanidinopropionic acid, Met-Leu, Glu-Ile and 5,6,8-trihydroxy-2-methylbenzo[g]chromen-4-one). By jointly analysing the transcriptomics and metabolomics results, we discovered 8 candidate genes (ADCYAP1, GAL, EDN2, EDN1, MC5R, S1PR4, LOC113843450, and IAPP) and one candidate metabolite (adenosine) that regulates aggressive pecking behaviour in ducks. The candidate genes and metabolites may be involved in regulating aggressive pecking behaviour by inducing neurodegeneration and disrupting neural excitatory-inhibitory homeostasis, which in turn affects central nervous system function in aggressive pecking and normal ducks. Our findings provide a new reference for revealing the underlying mechanism of aggressive pecking behaviour in ducks.

Effect of sea buckthorn extract on production performance, serum biochemical indexes, egg quality, and cholesterol deposition of laying ducks.

The purpose of this experiment was to study the effect of sea buckthorn extract (SBE) supplementation on the production performance, serum biochemical indexes, egg quality, and cholesterol deposition of laying ducks. A total of 240 23-week-old laying ducks (female ducks) with similar body weight were randomly divided into four treatment groups with 6 replicates of 10 each. The experimental groups were fed diets supplemented with 0, 0.5, 1.0, and 1.5 g/kg of SBE, respectively. The results showed that the addition of 1.0 g/kg SBE to the diet had significant increase (P < 0.05) in average egg weight and feed conversion ratio. The inclusion of SBE showed the significant improvement (P < 0.05) in yolk weight, shell strength, egg white height and haugh unit. Ducks fed with 1.0 and 1.5 g/kg SBE displayed a significant decrease (P < 0.05) in yolk cholesterol. The significant improvements were observed in the contents of total amino acid essential amino acids, non-essential amino acids, umami amino acids, monounsaturated fatty acids, and docosahexenoic acids of eggs (P < 0.05) when supplemented with SBE. However, the contents of total saturated fatty acids, polyunsaturated fatty acids, n-3 polyunsaturated fatty acids and n-6 polyunsaturated fatty acids in eggs showed decrease when ducks fed with SBE diets (P < 0.05). SBE diets may reduce (P < 0.05) the levels of serum total cholesterol, triglyceride, and low-density lipoprotein cholesterol, while increased (P < 0.05) the levels of serum superoxide dismutase, total antioxidant capacity, and glutathione catalase compared to the control. The levels of serum immunoglobulin G, immunoglobulin A and immunoglobulin M were improved in SBE diets (P < 0.05) in comparation to the control. The addition of SBE to diets can improve feed nutrient utilization, increase egg weight, optimaze egg quality and amino acid content in eggs, reduce blood lipids, improve fatty acid profile and yolk cholesterol in eggs, and increase antioxidant capacity and immunity in laying ducks.