Dietary chromium picolinate of varying particle size improves carcass characteristics and insulin sensitivity in finishing pigs fed low- and high-fat diets

The aim of the present study was to evaluate the effect of the different-sized particles of chromium (Cr) picolinate (CrPic) and dietary fat on growth performance, carcass traits and insulin sensitivity of finishing pigs. Ninety-six Large White × Landrace gilts were stratified on bodyweight, housed in pens of three pigs and then, on a pen basis, randomly allocated to eight treatment groups in a 2 × 4 factorial design for 6 weeks. The respective factors were dietary fat (2.2% or 5.7%) and dietary CrPic (0 mg/kg, 400 mg/kgnormal-size CrPic, 400 mg/kg 1-μm CrPic (μCrPic), or 400 mg/kg 100-nm CrPic (nCrPic)). Over the first 21 days, average daily gain (ADG) was increased by dietary CrPic (0.94 vs 1.01 kg/day, P = 0.021), although there was no difference (P = 0.17) between the CrPic particle sizes. High dietary fat also increased ADG over this period (0.96 vs 1.03 kg/day, P = 0.013). However, the responses to both dietary CrPic and fat diminished over time and so there was no effect of CrPic (P = 0.35) or fat (P = 0.93) on ADG over the full 42 days. Dietary CrPic increased carcass weight and muscle depth and decreased P2 backfat. Furthermore, dietary Cr decreased plasma insulin (7.66 vs 5.09 mU/L, P = 0.018) and the homeostatic model assessment (1.25 vs 0.82, P = 0.009), indicating an improvement in insulin sensitivity. In conclusion, dietary Cr can increase ADG and improve carcass traits and insulin sensitivity in lean pigs. There were few differences among particle sizes, possibly because the response to dietary CrPic may already be maximised at 400 mg/kg.

Effects of supplemental copper and chromium on the serum and egg traits of laying hens

1. This study investigated the effects of supplemental copper and chromium on the serum and egg traits of laying hens using 144 forty-five-week-old White Leghorn layers. The hens were randomly assigned into 9 groups to conduct this 3 copper (0, 125 and 250 mg/kg as copper sulphate) x 3 chromium (0, 800 and 1600 microg/kg as chromium picolinate) factorial trial. 2. Egg yolk cholesterol was significantly reduced by supplementary copper (Cu) and chromium (Cr) and there was an interaction between Cu and Cr supplementation. Egg production, egg weight, eggshell strength and eggshell thickness were not influenced by Cu or Cr supplementation. 3. Serum cholesterol concentration was decreased by Cu supplementation and very low-density lipoprotein (VLDL) was reduced markedly by both Cu and Cr. On the other hand, high-density lipoprotein (HDL) was significantly increased by Cu and Cr. Interaction occurred between Cu and Cr in the VLDL and HDL parameters. Supplmentary Cu also reduced VLDL-cholesterol (VLDL-C) and enhanced HDL-cholesterol (HDL-C), while supplemental Cr had a contrary effect on these two parameters. 4. If minimum egg cholesterol content is the criterion, this study suggests that 125 mg/kg of Cu together with 800 to 1600 microg/kg of Cr provide adequate supplementary concentrations for laying hens.

Lipoprotein profiles and components in Tsaiya ducks under ad libitum feeding and fasting

This study investigated lipoprotein compositions and distribution in Tsaiya ducks under ad libitum feeding and fasting. The study was conducted on each of thirty Tsaiya ducks over two 4-week periods. Each of the 30 Tsaiya ducks was randomly allocated into an ad libitum feeding group or a 3-day fasting group during the growing period (8-12 weeks old) and during the initial laying period (26-30 weeks old; 10-14 weeks after the onset of laying), respectively. Experimental results indicated that HDL (high-density lipoprotein) is the primary lipoprotein species in growing ducks but that in laying ducks the major population of lipoprotein is VLDL (very low density lipoprotein). Protein and cholesteryl ester were identified as the major components of HDL during both periods; triacylglycerol (TG) was the largest proportion of VLDL in both periods. In laying ducks VLDL contains more TG than in growing ducks; VLDL particle sizes in laying ducks were larger than in growing ducks. Fasting significantly decreased VLDL levels during both periods. The TG content in most lipoproteins was also decreased by fasting during both test periods. In contrast, the cholesteryl ester and free cholesterol in most lipoproteins were increased by fasting. The particle size of HDL and VLDL also decreased during fasting. This study indicated that lipoprotein profiles and components in Tsaiya ducks during the laying period were different from during the growing period and were affected by fasting.

Effects of chromium nicotinate on performance, carcase characteristics and blood chemistry of growing turkeys

1. The objective of this trial was to study the effects of chromium nicotinate (Cr) supplementation on the performance, carcase characteristics and blood constituents of 9 to 22 week-old male turkeys. 2. Fifty-four 8-week-old male turkeys weighing 2.9 +/- 0.28 kg were allocated at random into 9 groups with 3 dietary treatments and 3 replicates. The dietary treatment was different dietary concentrations of chromium in the basal diet, to provide 0 (control), 1 or 3 mg/kg. The feeding trial lasted for 14 weeks. 3. Results showed that 1 mg/kg chromium supplementation significantly improved weight gain and food intake at 9 to 18 weeks of age but did not significantly influence performance at 19 to 22 week of age. The breast and thigh muscle were significantly increased in birds receiving 1 mg/kg chromium supplementation but were decreased by 3 mg/kg of supplementation. 4. Dietary chromium supplementation did not significantly influence other serum constituents, including insulin, HDL, VLDL+LDL, HDL-C, VLDL-C+LDL-C, total protein, albumin, and gamma-globulin at 18 and 22 weeks of age. 5. The serum triacylglycerol (TG) and uric acid contents were significantly increased, while glycerol and alpha-globulin were significantly reduced by 3 mg/kg chromium supplementation. However, 1 mg/kg chromium supplementation significantly reduced serum cholesterol and glycerol at 18-weeks old. At 22 weeks of age, 1 mg/kg chromium supplementation significantly increased serum glucose and decreased the uric acid concentration whereas 3 mg/kg chromium supplementation significantly increased the creatinine concentration and decreased beta-globulin concentration.

The effect of supplementary dietary L-carnitine on the growth performance, serum components, carcase traits and enzyme activities in relation to fatty acid beta-oxidation of broiler chickens

1. This study investigated the effects of supplementary dietary L-carnitine on the performance, serum components, carcase traits and specific activities of hepatic enzymes related to beta-oxidation of fatty acids in broiler chickens. One hundred and eighty 1-d-old broilers were divided into 2 groups, each with 3 replicates, and given diets supplemented with 0 and 160 mg L-carnitine/kg for 6 weeks. 2. Experimental results indicated that supplementary carnitine did not significantly influence the performance and carcase characteristics of the broilers. 3. The serum triacylglycerol (TG) and nonesterified fatty acid (NEFA) concentrations in the carnitine supplemented group were significantly lower than that in the control group (P < 0.05). However, the effect on serum cholesterol, phospholipids concentrations and lipoprotein profiles were not significant (P > 0.05). 4. Carnitine palmitoyl transferase activity in the carnitine-supplemented group was significantly (P < 0.05) higher than in the control; however, carnitine supplementation did not significantly affect the activities of other fatty acid beta-oxidation enzymes. 5. The results in this study demonstrated that supplementary carnitine facilitated fatty acid transportation and did not influence the performance or carcase characteristics of broilers.

Performance, serum characteristics, carcase traits and lipid metabolism of broilers as affected by supplement of chromium picolinate

1. This study investigated the effects of dietary supplementation with chromium picolinate on the performance, serum and carcase traits and lipid metabolism of broilers. In trial 1, 120 1-day-old broilers with an equal number of males and females were assigned at random to 4 groups with 3 replicates. Four treatments with dietary supplements of 0 (control), 800, 1600 and 3200 microg/kg of chromium picolinate were used. In trial 2, 6-week-old broilers (20) were used to determine how supplements of 0, 200, 400 and 800 microg/kg chromium in an incubation medium influence their hepatocyte lipogenic capacity and adipocyte lipolysis, in vitro. 2. Dietary supplements of 1600 and 3200 microg/kg chromium in broiler diets significantly increased food consumption (P<0.05); 1600 microg/kg markedly improved weight gain (P<0.05); 1600 and 3200 microg/kg groups showed increased liver lipid content (P<0.05). However, the abdominal fat content tended to decrease in these 2 groups. 3. Dietary supplements of 1600 and 3200 microg/kg of chromium decreased serum glucose and nonesterified fatty acids (NEFA) concentrations while increasing serum phospholipid content (P<0.05). Insulin concentration decreased only in birds receiving 3200 ppb chromium (P<0.05). Serum triacylglycerol (TG) clearance rate in chromium-supplemented groups was markedly enhanced (P<0.05). 4. In addition, chromium supplemented groups had increased serum HDL contents and also reduced serum VLDL and LDL contents (P<0.05). 5. Trial 2 indicated that lipogenesis from [U-14C]glucose by isolated hepatocytes was significantly enhanced by 400 ppb chromium (P<0.05). 6. The results from this study demonstrate that a supplement of 1600 microg/kg of chromium picolinate in the ration influences the growth, carcase, serum traits and lipid metabolism of broilers.