Evaluation of the toxicity of alum (aluminum sulfate) in young broiler chickens.

Two experiments were conducted to characterize the toxicity and evaluate the efficacy of alum to increase intestinal strength in young broiler chicks. Cobb x Cobb male broiler chicks were placed in an experimental design consisting of six dietary treatments of alum (control, 0.23, 0.47, 0.93, 1.9, and 3.7%) with four replicate pens of 10 broilers per pen. The chicks were housed in electrically heated batteries and provided the treatments for ad libitum consumption from 1 d to 3 wk of age. Alum significantly (P < or = 0.05) decreased body weights at 1.9 and 3.7% in Experiment 1 and at 0.93, 1.9, and 3.7% in Experiment 2. Feed conversion and the relative weight of the gizzard were increased in both experiments at 3.7%. Serum phosphorus was decreased at 1.9 and 3.7% in Experiment 1 and at 3.7% in Experiment 2. Intestinal and bone strength were decreased in both experiments at 3.7%. Bone ash was reduced at 3.7% in Experiment 2, bone S levels increased at 1.9 and 3.7% in Experiment 1 and at 3.7% in Experiment 2, and bone Al levels were elevated in both experiments at 3.7%. Muscle levels of P and S decreased, and that of Ca increased at 3.7%. Aluminum levels were not elevated in muscle tissues. These data indicate that alum can be toxic to young broiler chicks, but at levels that would not be expected to be reached through litter consumption, and that alum did not increase intestinal strength.

Effect of gonadal steroids on bone and other physiological parameters of male broiler chickens.

Comparative studies of the effects of estradiol, progesterone, testosterone, cholesterol, and megestrol on juvenile chickens were carried out to determine their effects on bone and other physiological parameters. The chickens were implanted at 6 wk of age with ethylene-vinyl acetate copolymers containing steroids equivalent to a weekly dose of 10 mg/kg body weight for 3 consecutive wk. Estradiol caused a gain in body weight and relative liver weight but suppressed the growth of comb and testis. It also increased several serum variables, including triglycerides, cholesterol, calcium, phosphorus, and iron, and reduced testosterone levels. Testosterone produced an increase in comb weight and decreased both testicular and bursal weights. Growths of testis and comb were suppressed in progesterone-implanted chickens, as was the level of serum testosterone. Megestrol stimulated liver growth and increased serum testosterone levels. The lengths, relative weights, diaphyseal diameters, and ash percentages of both femur and tibia did not change significantly due to any treatment except that estradiol reduced tibial weight. Both progesterone and megestrol increased fibular growth plate alkaline and tartarate-resistant acid phosphatase activities. Other steroids did not affect these or the levels of calcium and of phosphorus of the fibular growth plate. Only testosterone caused a marked increase in the breaking strengths of both femur and tibia in all three parameters, i.e. load at yield, Young's modulus, and stress at yield responses. These findings suggest that the effects of steroids on bone in juvenile chickens may be limited.