Leucine levels in low protein diets for pigs in the initial phase

Abstract

The objective of this study was to evaluate the standardized ileal digestible (SID) leucine levels in low crude protein diets on Performance, backfat thickness, longissimus dorsi depth and biochemical blood parameters of starting pigs. A total of 50 pigs, with initial weight of 11.14±0.24 kg; were distributed in a randomized blocks design with five treatments (1.10; 1.25; 1.40; 1.55 and 1.70% SID leucine), five replicates and two animals per experimental unit, comprised for a barrow and a gilt. The feed conversion ratio (FCR) reduced (P=0.018) due to the increasing SID leucine levels, without affecting other growth performance parameters (final weight, average daily feed intake, average daily gain, backfat thickness, longissimus dorsi depth and lean meat percentage). There was a quadratic effect for plasma triglyceride (P=0.049) and plasma urea (P=0.001). The optimal SID leucine levels obtained for triglycerides and urea were 1.16% and 1.24%, respectively, by associating the quadratic model with the Linear Response Plateu. Low crude protein diets with SID leucine levels up to 1.70% improved the feed conversion with desired urea and triglycerides concentration in blood plasma achieved at 1.16% and 1.24%, respectively.

α‐Ketoisocaproate and β‐hydroxy‐β‐methyl butyrate regulate fatty acid composition and lipid metabolism in skeletal muscle of growing pigs

“…The Leu content was 1.23% in all groups except the Leu group, whose Leu content was doubled (2.46%). The Leu content of 1.23% was equal to the recommendation of the NRC (2012) for 10-25 kg pigs and was considered to be optimal to obtain desired TAG concentration in serum of 10-25 kg pigs (Huepa et al, 2017). The concentration of KIC utilized is equal to that of Leu to emulate the in vivo catabolism of Leu that would occur under normal conditions .…”