Three experiments were conducted to evaluate chromium picolinate (CrPic) in growing-finishing pigs. Treatments were replicated four times within each experiment with three pigs per replicate in Exp. 1 and four pigs per replicate in Exp. 2 and 3. Average initial weights were 37.8, 30.5, and 22.4 kg in Exp. 1, 2, and 3, respectively. In Exp. 1, the basal corn-soybean meal diet (B, 120% NRC Lys) was supplemented with 0, 25, 50, 100, or 200 ppb of Cr from CrPic. Daily gain was increased (Cr cubic, P < .02) and serum cholesterol decreased (Cr cubic, P < .08) by addition of CrPic. In Exp. 2, the basal diet was supplemented with 0, 100, 200, 400, or 800 ppb of Cr from CrPic. Daily gain and ADFI were decreased (Cr linear, P < .05) by CrPic. Serum cholesterol also was decreased (Cr quadratic, P < .05) by CrPic. Longissimus muscle area (LMA) and percentage of muscling (MUS) were increased (Cr quadratic, P < .01) and 10th rib fat (TRF) was decreased (Cr quadratic, P < .01) by CrPic. In Exp. 3, pigs were allotted to the following treatments: 1) B, 2) B + 1,467 ppb of picolinate (Pic), 3) B + 200 ppb of Cr from CrCl3.6H2O, 4) B + 1,467 ppb of Pic + 200 ppb of Cr from CrCl3.6H2O, 5) B + 100 ppb of Cr from CrPic, or 6) B + 200 ppb of Cr from CrPic. Longissimus muscle area and MUS were increased (P < .01) and TRF decreased (P < .01) in pigs fed CrPic but not in pigs fed CrCl3.6H2O and(or) Pic.(ABSTRACT TRUNCATED AT 250 WORDS)

Two experiments were conducted to evaluate the effect of Cr as Cr tripicolinate (CrPic) on growth, glucose tolerance, insulin sensitivity, plasma metabolites, and growth hormone (GH) in pigs. Pigs were fed a control diet or a diet supplemented with 200 micrograms of Cr/kg of diet as CrPic. Thirty (15 per diet, initial BW was 21.3 kg) and 24 (12 per diet, initial BW was 24.9 kg) crossbred barrows were used in Exp. 1 and 2, respectively. The diets were formulated to provide 120% of the lysine requirement for 20- to 50-kg pigs. A glucose tolerance test (IVGTT; 500 mg of glucose/kg BW) and an insulin challenge test (IVICT; .1 IU of porcine insulin/kg BW) were conducted. In addition, during Exp. 1, a GH-releasing hormone (GHRH) challenge was conducted. All data were pooled across experiments, except where noted. Average daily gain, ADFI, gain/feed, and fasting (15 to 18 h) plasma glucose and total protein concentrations were not affected (P > .10) by dietary treatment. Fasting plasma cholesterol (P < .05) was increased and NEFA (Exp. 2 only, P < .02), urea N (P < .07), and insulin (P < .10) concentrations were decreased in pigs fed CrPic. During the IVGTT and IVICT, glucose disappearance rate (k, percentage/minute) was increased (P < .04) and glucose half-life (t1/2, minutes) was decreased (P < .04) in pigs fed CrPic; however, insulin kinetics were not altered (P > .10). During the GHRH challenge, pigs fed CrPic had decreased (P < .09) area under the response curve for GH.(ABSTRACT TRUNCATED AT 250 WORDS)

1. Since high concentrations of zinc are associated with reduced crop yields, environmental concerns are emerging regarding zinc accumulation in areas where poultry production is prevalent. This study investigates growth performance and zinc utilisation during the life cycle of broilers when diets were supplemented with various concentrations of zinc from two different sources. 2. A total of 740 Cobb 500 1-d-old male broiler chicks was randomly distributed into 88 battery cages. Excreta were collected over a 48-h period on d 10, 17, 24, 31, 38, and 45 to measure zinc excretion on a dry matter basis. 3. During the 45-d experimental period, broilers were given a maize-soybean meal basal diet (30 mg/kg zinc) supplemented with 0, 20, 40, and 80 mg/kg of zinc from zinc sulphate, Availa Zn amino acid complex, or an equal combination of zinc sulphate and Availa Zn amino acid complex. 4. Progressive additions of zinc to the basal diet significantly increased body weight gain of broilers, but did not affect feed conversion or mortality. Optimum body weight gain was achieved at 80 mg/kg supplemental zinc, which exceeds the NRC recommendations of 40 mg/kg. 5. During each excreta collection period, increased supplemental zinc concentrations significantly increased zinc excretion. However, the zinc source did not influence zinc utilisation. 6. As compared with zinc sulphate supplementation, the cumulative zinc excretion data indicate that adding zinc to the basal diet in the form of Availa Zn amino acid complex decreased zinc excretion.

An experiment was conducted to evaluate the effect of dietary chromium picolinate (CrP) on growth and body composition of pigs. Twenty-four barrows (three from each of eight litters) were randomly allotted within litter to one of three treatments: 1) basal (B) diet from 19.1 to 106.4 kg BW (Control); 2) B from 19.1 to 57.2 kg BW and then B + 200 ppb of chromium as CrP from 57.2 to 106.4 kg BW (CrP-F); and 3) B + 200 ppb of chromium as CrP from 19.1 to 106.4 kg BW (CrP- GF). Average daily gain and ADFI were reduced (P < .08) and first rib fat thickness was increased (P < .08) in pigs fed CrP-GF compared with pigs fed the Control diet. Specific gravity of the carcass was not affected (P > .10) by treatment. Tenth rib fat was reduced (P < .01) in pigs fed CrP-F compared with pigs fed CrP-GF, and percentage of muscle was increased in pigs fed CrP-F (P < .09) compared with pigs fed either the Control or CrP-GF diets. Leaf fat (P < .05) and lung weights (P < .08) were reduced in pigs fed CrP-F compared with pigs fed CrP-GF. As determined by physical-chemical separation, pigs fed CrP-GF had an increased (P < .07) percentage of intermuscular fat compared with pigs fed the Control or CrP-F diets. Pigs fed CrP-F had a lesser (P < .07) percentage of total fat and a greater (P < .07) percentage of muscle than pigs fed the Control or CrP-GF diets. As determined by mechanical-chemical separation, pigs fed CrP-F had a greater (P < .10) percentage of moisture than pigs fed the Control diet and a lesser (P < .10) percentage of fat and a greater (P < .06) percentage of ash than pigs fed the Control or CrP-GF diets. Pigs fed CrP-GF had an increased (P < .04) daily fat accretion compared with pigs fed CrP-F. Sensory and shear force values were not affected by CrP, with the exception that meat from pigs fed CrP-GF had a greater (P < .10) shear force value than meat from pigs fed CrP-F. These results suggest that dietary supplementation of CrP in the finishing phase of pig production may increase muscle and decrease fat deposition; however, not all measures of muscling or fatness were improved by CrP.

The objective of the current study was to determine the bioavailability of an organic zinc source (Availa-Zn) compared with zinc sulfate in a European-type broiler diet. A total of 480 one-day-old male Ross 308 broilers were housed in 48 digestibility cages (10 birds per cage), being randomly divided over 9 treatments. At d 3, the number of birds was standardized to 8. Birds were fed a basal wheat-maize-soya diet (containing 33.5 mg of Zn/kg) with different supplementation levels of zinc (reference zinc source: inorganic zinc sulfate: 0, 5, 10, 15, 20, and 40 mg of Zn/kg of feed; test zinc source: Availa-Zn: 0, 5, 10, 15 mg of Zn/kg of feed). Production performance and tibia zinc content were measured. There were no differences in production performance between the different zinc sources when fed to broilers until 21 d of age. Tibia zinc content was increased linearly with the dietary zinc content up to 20 mg/kg zinc sulfate. The relative biological value of organic zinc was 1.64 compared with zinc sulfate as a reference zinc source (1.00), as indicated by the slope ratio of the linear response curves for both zinc sources, using tibia zinc content as a response parameter. In a practical European broiler diet, the organic Availa-Zn had a higher bioavailability than inorganic zinc sulfate.