ABSTRACT
Long-term feeding trials examining the incorporation of conjugated linolenic acids (CLnA) into the diet of laying hens are lacking. In the present study, we compared two diets in sixty-six red Sex-Link hens (33 hens/treatment), fed for 26 weeks. The control diet was high in oleic acid, while the test diet was high in α-linolenic acid (ALA) and punicic acid (PunA). No significant differences were observed between treatments for hens' performance, egg weight and yolk weight. In contrast, dietary ALA and PunA resulted in a significant increase in n-3 PUFA, rumenic acid (RmA) and PunA contents in egg yolk, as well as in the liver, heart, muscle and adipose tissue of the hens. Other conjugated dienes resulting from the metabolism of PunA or RmA also accumulated in the egg yolk and tissues. Unlike DHA, which was exclusively distributed in phospholipids, ALA, RmA and PunA were preferably distributed in triglycerides.
ABSTRACT
The methanogenic and acidogenic potentials of six different agroindustrial residues, i.e. of fruit pulps and brewery residues, were determined. For all substrates, the methanogenic conversion yield was systematically higher than the acidogenic one in Chemical Oxygen Demand (COD) terms, ranging from 0.46 to 0.87â¯gCOD_CH4/gCOD_substrate_fed and from 0.24 to 0.56â¯gCOD_tVFA/gCOD_substrate_fed, respectively. During methanogenic conversion, brewery trub exhibited the highest methane potential (304mlCH4/gCOD_substrate). Trub also exhibited the highest total volatile fatty acids (tVFA) concentrations in the mixed liquor (ML) during acidogenic conversion (29.7â¯gCOD_tVFA/kgML). Acetic, butyric and caproic acids were the main carboxylates produced by the different substrates. Despite the lower conversion yields, the economic value of the acidogenic product (carboxylate streams) is higher than that of methanogenic conversion (methane) due to the higher value of carboxylates and their potential use in finer applications (e.g. bio-based products) compared to energy production form methane.
