Grape seed extract and chromium nicotinate reduce impacts of heat stress in Simmental × Qinchuan steers

To assess the impacts of grape seed extract (GSE) fed with or without chromium nicotinate (CN) on beef steers under heat stress conditions, 40 Simmental × Qinchuan steers (400 ± 10 days old; 410 ± 8.0 kg) were randomly assigned to one of four diets (n = 10 per group): basal diet (CON group); basal diet + 33 mg/day CN (CN group); basal diet + 65 mg/kg DM GSE (GSE group); and basal diet + 33 mg/day CN + 65 mg/kg DM GSE (CN + GSE group). This study was conducted in summer and the steers were housed in outdoor shaded pens (10 steers/pen) and fed individually. The experiment lasted for 35 days, the first 7 days for diet and housing condition adaptation. The amount of feed intake was recorded daily; individual bodyweight was recorded on Days 8, 22, and 36. On Day 36 before feeding, six steers per group were slaughtered for collection of blood and tissue samples. Average daily liveweight gain and dry matter intake of steers were increased by the GSE, CN, and CN + GSE treatments (P < 0.05). Dietary treatments increased the activities of glutathione peroxidase and total superoxide dismutase in plasma (P < 0.05) and plasma concentration of interleukin 10 on Days 22 and 36 (P < 0.05), whereas decreased plasma concentration of tumour necrosis factor-α on Day 22 (P < 0.05). Overall, supplementation of GSE alone or with CN had positive effects on the growth performance of steers under heat stress conditions.

Effect of different levels of chromium nicotinate on growth performance and antibody titre responses to Newcastle and Avian Influenza disease in heat-stressed broiler chicks

High ambient temperature reduces feed intake, live weight gain, and feed efficiency (Siegel, 1995), thus negatively influencing the performance of broilers. Heat stress has also been shown to suppress immune responses of broiler. Chromium is an essential nutrient required to promote the action of insulin in body tissues so that the body can use sugars, proteins and fats. Cr deficiency can disrupt carbohydrate and protein metabolism, reduce insulin sensitivity in peripheral tissues and impair growth rate (Vincent, 2000).Chromium is important in altering the immune response by immunostimulatory or immunosuppressive processes as shown by its effects on T and B lymphocytes, macrophages and cytokine production. Dietary chromium supplementation has been reported to have a positive effect on growth rate and feed efficiency of growing poultry under stress conditions (Sahin et al., 2002). Another reason for supplementing chromium is due to the fact that chromium is excreted excessively during stress (Anderson, 1994). Also the dietary requirement of livestock for chromium has not been defined yet (NRC, 1997). This study was to investigate the effects of different levels of Cr nicotinate on the growth performance and antibody titres against Newcastle and Influenza disease in broilers.

Effects of dietary additions of modified tall oil, chromium nicotinate, and L-carnitine on growth performance, carcass characteristics, and bacon characteristics of growing-finishing pigs

Eighty gilts were supplemented with modified tall oil (MTO), chromium nicotinate (CrNic), and L-carnitine to determine effects on growth and meat quality characteristics. Pigs were assigned to one of eight treatments in a 2 × 2 × 2 factorial with main effects of MTO (0 or 0.5%), CrNic (0 or 50 μg kg-1), and L-carnitine (0 or 50 mg kg-1). Pigs fed MTO had increased (P = 0.03) average daily gain and pigs fed CrNic had improved (P = 0.02) gain:feed. Bellies from pigs supplemented with MTO with no CrNic were firmer (P < 0.05) than bellies from all other treatment combinations. No differences (P > 0.05) were detected for longissimus muscle (LM) visual or objective color values. Furthermore, no differences (P > 0.05) were detected for LM Warner-Bratzler shear force or sensory traits. Bacon from pigs fed MTO had firmer (P < 0.05) slices than bacon from pigs fed no MTO.These data suggest improvements in growth performance from addition of 0.50% MTO and(or) 50 μg kg-1 CrNic to diets of finishing gilts. Supplementing with MTO, CrNic, and L-carnitine had minimal effects on carcass, LM color and sensory, or bacon characteristics. Key words: Pork, modified tall oil, chromium nicotinate, L-carnitine, longissimus muscle, bacon