Effects of vitamin A supplementation in young lambs on performance, serum lipid, and longissimus muscle lipid composition

Abstract

Forty crossbred wethers (BW = 28.7 kg) were used to evaluate the effects on LM lipid composition of diets containing high and low levels of vitamin A. Four treatments arranged as a 2 x 2 factorial with a completely random design were investigated: backgrounding (BG) and finishing (FN) with no supplemental vitamin A (LL); BG with no supplemental vitamin A and FN with high vitamin A (6,600 IU/kg of diet, as fed) supplementation (LH); BG with high vitamin A supplementation and FN with no vitamin A supplementation (HL); and BG and FN with high vitamin A (HH) supplementation. Diets included cracked corn (62.4%), soybean meal (16.0%), cottonseed hull pellets (14.8%), and supplement (7%), and contained <100 IU of vitamin A/kg (as fed) from carotenes before vitamin A was added. During the BG period (d 1 to 56), feed intake was restricted to achieve 0.22 kg of ADG. During the FN period (d 57 to 112), lambs consumed the same diet ad libitum. Lambs were weighed every 14 d, and blood was sampled every 28 d to evaluate changes in serum fatty acids and vitamin A levels. Lambs were slaughtered after 112 d. Lipid composition was determined for liver and LM. There were no treatment differences (P > 0.05) in feed intake, ADG, or final BW. Carcass weights were not affected by vitamin A treatment (P > 0.20), although backfat thickness tended to be different between HL and LL lambs (0.80 vs. 0.64 cm, respectively; P = 0.08). Carcasses from the HH group had greater (P < 0.05) marbling scores than those from the LL group (514 vs. 459) and had 25.8% more extractable intramuscular lipids (3.88 vs. 3.08% for HH and LL, respectively; P < 0.05); the LH and HL treatments were intermediate. Interestingly, the LL group had the greatest increase in serum fatty acids throughout the experimental period (change of 127 vs. 41 microg/g for LL and HH, respectively; P < 0.01). The degree of saturation of fatty acids was not affected by treatment (P = 0.18) in the serum but was affected in the longissimus thoracis fat. Oleic acid increased and linoleic acid decreased in the longissimus thoracis of HH-treated lambs (P < 0.02). These data suggest that increases in total intramuscular lipids may be achieved with high levels of vitamin A supplementation for 112 d in young lambs.

Effects of Vitamin A on Growth Performance, Antioxidant Status and Blood Constituents in Lactating Grey Goat

“…Dry Spanish potato vine was the only forage source and the grain sources contained either very low or undetectable carotene. Therefore, the diets were assumed no carotenes derived vitamin A (Arnett et al, 2007).…”

Retinoic acid modulates lipid accumulation glucose concentration dependently through inverse regulation of SREBP‐1 expression in 3T3L1 adipocytes

“…Rats given the cafeteria diet supplemented with a high concentration of vitamin A showed increased adiposity compared with rats given the same diet containing a low amount of vitamin A (Redonnet et al 2008). In young lambs, high levels of vitamin A supplementation led to an increase in the total intramuscular lipid level (Arnett et al 2007).…”

“…In young lambs, high levels of vitamin A supplementation led to an increase in the total intramuscular lipid level (Arnett et al . ).…”

Effect of dietary supplemental vitamin A concentration on performance, carcass merit, serum metabolites, and lipogenic enzyme activity in yearling beef steers123

“…In addition, Pyatt et al (2005) found no correlation (P > 0.10) between marbling score and serum retinol concentration. Arnett et al (2007) showed that marbling score increased in lambs fed 6,600 vs. 0 IU of supplemental vitamin A/kg, and they found a positive correlation (r = 0.30; P < 0.10) between marbling score and serum retinol. Similarly, research conducted to evaluate various vitamin A supplementation and restriction strategies (Gorocica-Buenfil et al, 2007a,b,c, 2008 showed mixed results.…”