Intestinal fatty acid digestion and energy utilization in lambs infused with different plant oils into the abomasum

International audienc

Mammary Uptake of Plasma Amino Acid in Frequent Milking Cows under an Automatic Milking System

Increasing milking frequency (MF) with automatic milking systems (AMS) has been known to increase milk production in dairy cows. The enhanced milk production with increasing milking frequency may change the uptake and utilization of amino acids (AA) by mammary gland. The aim of this study was to evaluate the plasma AA uptake by mammary gland and the ratio of the mammary uptake to milk output of AA in early lactation cows with different MF using AMS. Twelve Holstein cows were assigned to 2 times and 4 times MF treatments. Cows were fed a partial mixed ration ad libitum and a concentrate diet at every milking. At days 20, 35, and 50 postpartum, blood was collected from coccygeal artery and subcutaneous abdominal vein at 14:00 h, and the milk samples were also taken. Milk production and protein yield were greater in 4 times milking cows (P<0.001). Mammary uptakes of most essential AA except for threonine and valine were higher (P<0.05) in 4 times milking cows than in 2 times milking cows, though those of non-essential AA did not differ between treatments. In contrast, the uptake to output ratio of essential AA except for valine did not differ between treatments, whereas those of glutamine, glutamate and glycine were lower (P<0.08) in 4 times milking cows than in 2 times milking cows. These results indicate that increasing MF by AMS may enhance the mammary uptake and use of some essential AA for milk protein synthesis

Enteric Methane Emissions and Rumen Fermentation Profile Treated by Dietary Chitosan: A Meta-Analysis of In Vitro Experiments

Chitosan is a natural compound obtained from deacetylation of chitin, which is a biopolymer present in the exoskeleton of crustaceans such as crabs and shrimp. The present study aimed to perform a meta-analysis from published studies regarding the effects of chitosan on methane emission and rumen fermentation profile of in vitro batch culture experiments. A total of 41 studies from 12 articles were integrated into a database. Parameters included were gas production, methane emission, rumen fermentation characteristics, microbial population, nutrient digestibility, and fatty acid profile. Data were analyzed according to mixed model methodology in which different studies were treated as random effects and chitosan addition levels were treated as fixed effects. Results showed that chitosan addition was able to reduce enteric methane emissions (p&lt;0.001). Such methane decrease was accompanied by a decline in the protozoa population (p&lt;0.05) and a tendency of methanogen reduction (p&lt;0.1). The increasing chitosan level was associated with a decrease in total VFA and ammonia concentrations (both at p&lt;0.001). Chitosan addition decreased acetate proportion (p&lt;0.001) while elevated propionate proportion (p&lt;0.001). Chitosan was associated with an increase of dry matter digestibility, crude protein digestibility, and neutral detergent fiber digestibility (p&lt;0.001). Chitosan increased concentrations of C18:3n3 (p&lt;0.05), conjugated linoleic acid (p&lt;0.01) and polyunsaturated fatty acids (p&lt;0.01) while decreased concentration of saturated fatty acids (p&lt;0.001). It can be concluded that chitosan addition can mitigate enteric methane emission and alters rumen fermentation profiles in a favorable direction