Lactobacillus sakei modulates mule duck microbiota in ileum and ceca during overfeeding.

The supplementation with Lactobacillus sakei as probiotic on the ileal and cecal microbiota of mule ducks during overfeeding was investigated using high-throughput 16S rRNA gene-based pyrosequencing and real-time PCR. The ducks were overfed with or without L. sakei for 12 d with 56% ground corn and 42% whole corn. Samples were collected before the overfeeding period (at 12 wk), at 13 wk (meal 12 of overfeeding), and at 14 wk (meal 24), 3 h postfeeding. Whatever the digestive segment and the level of intake, Firmicutes, Bacteroidetes, and Proteobacteria were the dominant phyla in the bacterial community of mule ducks (at least 90%). Before overfeeding, ileal samples were dominated by Clostridia, Bacteroidia, and Gammaproteobacteria (80% and up), and cecal samples by Bacteroidia and Clostridia (around 85%). The richness and diversity decreased in the ileum and increased in the ceca after overfeeding. Overfeeding increased the relative abundance of Firmicutes and especially the Lactobacillus group in ileal samples. Nonmetric multidimensional scaling profiles separated the bacterial communities with respect to overfeeding only in cecal samples. Richness indicators decreased after L. sakei has been added at mid-overfeeding only in the ileum. In the ceca, the decrease of these indexes only occurred at the end of overfeeding. The addition of L. sakei triggers major changes in the ileum, whereas the ceca are not affected. Lactobacillus sakei decreased the relative abundance of Bacteroides at mid-overfeeding and the relative abundance of Enterobacteria at the end of overfeeding in the ileum.

Genetic parameters of product quality and hepatic metabolism in fattened mule ducks.

Genetic parameters of traits related to hepatic lipid metabolism, carcass composition, and product quality of overfed mule ducks were estimated on both parental lines of this hybrid: the common duck line for the maternal side and the Muscovy line for the paternal side. The originality of the statistical model was to include simultaneously the additive genetic effect of the common ducks and that of the Muscovy ducks, revealing a greater genetic determinism in common than in Muscovy. Plasma metabolic indicators (glucose, triglyceride, and cholesterol contents) were heritable, in particular at the end of the overfeeding period, and heritabilities increased with the overfeeding stage. Carcass composition traits were highly heritable in the common line, with values ranging from 0.15 for liver weight, 0.21 for carcass weight, and 0.25 for abdominal fat weight to 0.32 for breast muscle weight. Heritabilities of technological outputs were greater for the fatty liver (0.19 and 0.08, respectively, on common and Muscovy sides for liver melting rate) than for the pectoralis major muscle (between 0.02 and 0.05 on both parental sides for cooking losses). Fortunately, the processing industry is mainly facing problems in liver quality, such as too high of a melting rate, than in meat quality. The meat quality appraisal criteria (such as texture and cooking losses), usually dependent on pH and the rate of decline of pH, were also very lowly heritable. This study demonstrated that genetic determinism of meat quality and ability of overfeeding is not similar in the common population and in the Muscovy population; traits related to fattening, muscle development, and BW have heritability values from 2 to 4 times greater on the common line than on the Muscovy line, which is relevant for considering different selection strategies.