Omega-3 polyunsaturated fatty acids provided during embryonic development improve the growth performance and welfare of Muscovy ducks (Cairina moschata).

The welfare of ducks can be affected by unwanted behaviors such as excessive reactivity and feather pecking. Providing long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) during gestation and early life has been shown to improve the brain development and function of human and rodent offspring. The aim of this study was to test whether the pecking behavior of Muscovy ducks during rearing could be reduced by providing LC n-3 PUFA during embryonic and/or post-hatching development of ducklings. Enrichment of eggs, and consequently embryos, with LC n-3 PUFA was achieved by feeding female ducks (n-3F) a diet containing docosahexaenoic (DHA) and linolenic acids (microalgae and linseed oil). A control group of female ducks (CF) was fed a diet containing linoleic acid (soybean oil). Offspring from both groups were fed starter and grower diets enriched with DHA and linolenic acid or only linoleic acid, resulting in four treatment groups with 48 ducklings in each. Several behavioral tests were performed between 1 and 3 weeks of age to analyze the adaptation ability of ducklings. The growth performance, time budget, social interactions, feather growth, and pecking behavior of ducklings were recorded regularly during the rearing period. No significant interaction between maternal and duckling feeding was found. Ducklings from n-3F ducks had a higher body weight at day 0, 28, and 56, a lower feed conversion ratio during the growth period, and lower reactivity to stress than ducklings from CF ducks. Ducklings from n-3F ducks also exhibited a significantly reduced feather pecking frequency at 49 and 56 days of age and for the whole rearing period. Moreover, consumption of diets enriched with n-3 PUFA during the starter and grower post-hatching periods significantly improved the tibia mineralization of ducklings and the fatty acid composition of thigh muscles at 84 days of age by increasing the n-3 FA content.

Sex impact on the quality of fatty liver and its genetic determinism in mule ducks.

Recent changes to French regulations now allow farmers to produce "foie gras" from both male and female mule ducks. The aim of this study was to assess the quality of female fatty liver and to compare, from a phenotypic and genetic point of view, liver quality in males and females. A total of 914 mule ducks (591 males and 323 females), hatched in a single pedigree batch, were reared until 86 d of age and then force-fed for 12 d, before being slaughtered. Carcasses and livers were weighed and liver quality was assessed by grading the extent of liver veining and measuring the liver melting rate, either after sterilization of 60 g of liver or pasteurization of 180 g of liver. Sexual dimorphism was observed in favor of males, with a difference of approximately 10% in carcass and liver weights and up to 54% for the liver melting rate. Moreover, one-third of female livers showed moderate to high veining, whereas this was not the case for male livers. The fatty livers of female mule ducks are, therefore, of poorer quality and could not be transformed into a product with the appellation "100% fatty liver." According to sex and parental line, heritability values ranged from 0.12 ± 0.05 to 0.18 ± 0.07 for fatty liver weight and from 0.09 ± 0.05 to 0.18 ± 0.05 for the 2 melting rate traits. The genetic correlations between the fatty liver weight and both melting rates were high (greater than +0.80) in the Muscovy population, whereas in the Pekin population, the liver weight and melting rates were less strongly correlated (estimates ranging from +0.36 ± 0.30 to +0.45 ± 0.28). Selection for lower liver melting rates without reducing the liver weight would, therefore, be easier to achieve in the Pekin population. Finally, as the 2 melting rate measurements are highly correlated (0.91 and over 0.95 for phenotypic and genetic correlations, respectively), we suggest using the easiest method, that is, sterilization of 60 g of liver.