Effects of low phytate barley (Hordeum vulgare L.) on zinc utilization in young broiler chicks.

Two 21-d experiments were conducted to evaluate the effects of low phytate barley (LPB) on Zn utilization by young broiler chicks and to determine the contribution of endogenous phytase, present in LPB. In the first experiment, ninety-six 1-d-old male chicks were assigned to a 2 x 3 factorial arrangement of treatments (4 pens of 4 chicks/treatment). Factors were barley type [wild-type barley (WTB) and LPB mutant M 955] and supplemental Zn (0, 10, or 20 mg of Zn/kg). In the second experiment, two hundred forty 1-d-old straight-run broiler chicks were assigned to a 2 x 2 x 3 factorial arrangement of treatments (4 pens of 5 chicks/treatment). Factors were barley type (WTB and LPB), autoclave treatment [nonautoclaved or autoclaved (121 degrees C, 20 kg/cm(2), 20 min)], and supplemental Zn (0, 10 or 20 mg of Zn/kg). Barley made up 60% of the diets and was the only source of phytate. On average, basal diets contained 26 mg of Zn/kg. Feed intake and body weight gain were greater (P < 0.05) in broilers fed LPB compared with WTB in experiment 2. Zinc concentration in toes and tibias were affected (P < 0.0001) by barley type (LPB > WTB) and supplemented Zn levels (20 > 10 > 0 mg of Zn/kg), and significant barley type x Zn interactions were also observed in both experiments. Substitution of LPB for WTB increased tibia and toe Zn by 46 and 25%, respectively, an increase comparable to that achieved with supplementing the diet with 20 mg of Zn/kg. No effect of autoclaving was observed for any variable in experiment 2. Retention of P and Zn was higher (P < 0.001) in chicks fed LPB compared with WTB in both experiments. Zinc retention was influenced (P < 0.0001) by dietary Zn, and barley type x Zn level interactions (P < 0.05) were observed in both experiments. Chicks fed LPB utilized more dietary Zn and P than those fed WTB, and this improved mineral utilization was not due to endogenous phytase present in barley.

Individual and combined effects of the Fusarium mycotoxins fumonisin B1 and moniliformin in broiler chicks.

The individual and combined effects of feeding fumonisin B1 (FB1; 0, 100, 200 mg FB1/kg) and moniliformin (M; 0, 100, 200 mg M/kg) were evaluated using a 3 x 3 factorial arrangement of treatments. Significant mortality (P < 0.05) occurred in chicks fed all diets containing 200 mg M/kg (50%-65%). Compared with controls and chicks fed FB1, both feed intake and body weight gain were decreased (P < 0.05) in chicks fed diets containing 100 mg M/kg. Chicks fed M had heavier heart weights (P < 0.05) than control chicks or chicks fed FB1. Compared with controls, chicks fed diets containing 200 mg M/kg or a combination of 200 mg FB1/kg and 100 mg M/kg had increased kidney and liver weights (P < 0.05). Significant FB1 by M interactions (P < 0.05) were observed for serum total protein and aspartate aminotransferase. Mild to moderate periportal extramedullary hematopoiesis and mild focal hepatic necrosis were observed in chicks fed FB1 alone. An increased incidence of large pleomorphic cardiomyocyte nuclei, loss of cardiomyocytes, and mild focal renal tubular mineralization were observed in chicks fed M alone. Both cardiac and renal lesions were observed in chicks fed combinations of FB1 and M. Data indicate FB1 and M, alone or in combination, can adversely affect chick performance and health at these dietary concentrations. The interactive effects of FB1 and M were not synergistic and were less than additive in nature. At the dietary concentrations studied, M is much more toxic to broilers than FB1.

Chronic effects of moniliformin in broiler and turkeys fed dietary treatments to market age.

Floor pen studies were conducted, with broilers from 1 to 7 wk of age and with turkeys from 1 to 14 wk of age, to evaluate the chronic effects of moniliformin (M). Fusarium fujikuroi (M-1214) culture material was added to typical corn-soybean basal diets to supply 0, 25, or 50 mg M/kg diet (broilers) or 0, 12.5, 25, 37.5, or 50 mg M/kg diet (turkeys). Compared with controls, chicks fed diets containing 50 mg M/kg consumed more feed, had lower body weight gain, were less efficient in converting feed to body weight gain, and had increased relative heart and proventriculus weights. Chicks fed the diet containing 50 mg M/kg also had significantly higher mortality and decreased mean corpuscular volumes compared with controls. Broilers fed 25 and 50 mg M/kg also had increased serum gamma glutamyltransferase activities. Feed intake, body weight gain, and feed conversion of turkeys fed dietary M were not affected. At 6 and 14 wk, turkeys fed 25, 37.5, or 50 mg M/kg diet had increased (P < 0.05) relative heart weights when compared with controls. At week 14, turkeys fed diets containing 37.5 or 50 mg M/kg also had increased (P < 0.05) relative liver weights compared with turkeys fed 0, 12.5, or 25 mg M/kg diet. Lesions, observed only in the hearts of broilers and turkeys fed 50 mg M/kg, were loss of cardiomyocyte cross striations, increased cardiomyocyte nuclear size, and an increased number of cardiomyocyte mitotic figures (turkeys only). Results indicate that > or = 37.5 mg M/kg is hepatoxic and > or = 25 mg M/kg is cardiotoxic to turkeys and 50 mg M/kg diet is toxic to broilers fed to market age.

Chronic effects of fumonisin B1 in broilers and turkeys fed dietary treatments to market age.

Floor pen studies were conducted with 270 broiler chicks and 144 turkey poults, all 1 wk old, to evaluate the chronic effects of fumonisin B1 (FB1). A completely randomized design was used in both studies with six pen replicates of 15 chicks or eight pen replicates of six poults assigned to each of three dietary treatments from Weeks 1 to 7 (broilers) or to Week 14 (turkeys). Fusarium moniliforme (M-1325) culture material was added to a typical corn-soybean basal diet to supply 0, 25, or 50 mg FB1/kg diet. Feed intake, body weight gain, and feed conversion of chicks were not affected (P > 0.05) by FB1. Turkeys fed 50 mg FB1/kg had significantly (P < 0.05) lower feed intake than the controls. Compared with controls, chicks and turkeys fed FB1 diets had significantly higher liver sphinganine to sphingosine ratios (P < 0.05). Relative organ weights of chicks were not affected (P > 0.05) by FB1, other than those chicks fed 25 mg FB1/kg, which had lower (P < 0.05) relative proventriculus weights than the chicks fed 0 or 50 mg FB1/kg. Broilers fed 50 mg FB1/kg had decreased serum calcium and increased serum chloride when compared to broilers fed 0 or 25 mg FB1/kg. Hematology was not affected (P > 0.05) by dietary FB1. No lesions were present in any organ examined microscopically. Results indicate that 50 mg FB1/kg diet is detrimental to turkeys but is not toxic to broilers fed to market age.