Effects of supplementing a feedlot diet with microalgae (Chlorella vulgaris) on the performance, carcass traits and meat quality of lambs

Abstract

This study evaluated the effect of different levels of fresh microalgae (Chlorella vulgaris) in a feedlot diet on the performance, carcass traits, and meat quality of lambs. Forty-five, four-month-old wether lambs were randomly assigned to one of three dietary treatments: 1) CONTROL, without algae; 2) MEDIUM, with 0.5 % dry matter (DM) algae; or 3) HIGH, with 1 % DM algae added to a basal diet consisting of barley hay and commercial feedlot pellets in a 41:59 ratio. The lambs were fed for 98 days and then slaughtered. Microalgae supplementation did not affect (P ≥ 0.09) growth performance, wool quality, rumen fermentation parameters, carcass weight, dressing percentage, or subcutaneous fat thickness of the lambs. However, microalgae supplementation at 0.5 % DM increased (P ≤ 0.05) the concentration of alpha-linolenic acid (ALA; C18:3n-3), arachidic acid (C20:0), and total omega-3 long-chain (n-3 LC) fatty acids in the longissimus lumborum et thoracis (LTL) muscle of lambs, compared to the CONTROL. Intramuscular fat (%) was similar between the CONTROL and the MEDIUM group (av. 3.65 %), but was lower (P = 0.044) in the HIGH group (3.1 %). Therefore, our results indicate that adding 0.5 % DM microalgae to lamb diets can increase the levels of alpha-linolenic acid and total n-3 LC PUFA in fresh lamb meat without affecting lamb performance or carcass characteristics.