Growth and development in rats and deficiency of magnesium and pyridoxine.

Eight-eight female weanling Sprague-Dawley rats were fed diets containing either 650 or 150 mg magnesium/kg diet and 7.0 or 3.5 mg pyridoxine-HCl/kg diet, in a 2 x 2 factorial arrangement, during growth, gestation, and lactation. The objective of the study was to determine whether concurrent dietary deficiencies of magnesium and pyridoxine were synergistic, additive, or antagonistic with regards to effects on reproductive performance, growth, and development of offspring, and tissue content of magnesium and calcium. Body weight of dams and pups was not different between groups until day 9 of lactation, at which point those animals in either low magnesium group weighed less than the other. Litter size and birth weight were not different. Development, as measured by timing of unfolding of the external ear, opening of both eyes, and clinical emergence of incisors, was delayed in pups from litters in the low magnesium groups. A synergistic effect on delay of onset of ear unfolding by deficiency of both magnesium and pyridoxine was observed. Calcium content of heart and kidney from dams was increased in the low magnesium groups. Renal calcium was not further increased by the level of pyridoxine deficiency in this study. The calcium to magnesium ratio in heart from pups was higher in those from litters in the low magnesium and pyridoxine group than in the others. Results indicate that simultaneous deficiencies of magnesium and pyridoxine may impair function synergistically. Because these two nutrients are often reported to be presented in inadequate amounts in diets of women in their reproductive years, the potential exists for impaired reproductive success.

Influence of dietary tetramethylthiuram disulfide (a fungicide) on growth and incidence of tibial dyschondroplasia in single comb White Leghorn chicks.

The effect of dietary tetramethylthiuram disulfide (TMTD) (0, 30, or 60 mg/kg diet) on the performance and incidence and severity of tibial dyschondroplasia (TD) in Single Comb White Leghorn (SCWL) chicks was studied in a 6-week experiment. Body weights (3 weeks of age) and bone ash (4 and 6 weeks of age) of chicks fed either 30 or 60 mg TMTD/kg diet were significantly lower compared to controls. Dietary TMTD, however, significantly increased the incidence and severity of TD in layer chicks with the highest incidence (69%) occurring in 6-week old-birds. This study showed that SCWL chicks were susceptible to TMTD-induced TD as early as 2-weeks of age and that the condition persisted throughout the growing phase.

Vitamin A toxicosis in the chick and turkey poults.

Susceptibility to vitamin A (vit A) toxicosis was compared in Single Comb White Leghorn chicks, broilers, and turkey poults by giving an aqueous vit A solution of varying concentrations by crop intubation. Results of these studies indicate a differential response to vit A toxicosis within breeds and across species. Pair-fed treatments clearly demonstrated that the effects of excess vit A on bone calcification were independent of anorexia. A comparison between turkey poults receiving either a constant dietary level of vit A or vit A by gavage showed that the latter markedly increased the severity of vit A. toxicosis.

Excess dietary vitamin A in the growing chick: effect of fat source and vitamin D.

Studies were conducted to determine the nutritional interrelationship between different fat sources, vitamin D3 (vit D) and excess dietary vitamin A (vit A) in the growing chick. Birds tolerated as much as 30 times the recommended level of vit A without compromising performance or skeletal development as measured by bone ash. The response to excess dietary vit A was not influenced by the type of dietary lipid (corn oil, tallow, or poultry oil). No nutritional interaction between vit A (1,500, 15,000, or 45,000 IU/kg) and vit D (100 or 1000 ICU/kg) was detected as measured by growth, bone ash, growth hormone, incidence of tibial dyschondroplasia (TD), or rickets. Serum alkaline phosphatase activity, however, was significantly affected by vit A, vit D, and age of the chicks. The higher vit D level significantly enhanced growth, bone ash, and reduced incidence of rickets, although it had no effect on incidence of TD.

Tibial dyschondroplasia in single-comb White Leghorn chicks fed tetramethylthiuram disulfide (a fungicide).

Supplementing a practical chick starter diet with 30 mg tetramethylthiuram disulfide per kg of diet produced tibial dyschondroplasia (TD) in single-comb white leghorn chicks without compromising growth or bone mineralization. The incidence and severity of the lesion increased over time, with the highest incidence (40%) occurring in 4-week-old chickens. Microscopically, the lesion was consistent with the description of TD in broilers. This is the first known report of TD in the layer-type chick, which heretofore was felt to be highly resistant to TD.

Avitaminosis K and the lack of heart lesions in poultry.

Poultry susceptibility to avitaminosis K-induced granulomatous endocardial lesions was studied in broiler and layer chicks. They were fed either a practical corn-soybean meal diet with and without added vitamin K (vit K), or a 61% raw sugar-isolated soybean protein diet (RS-IS) with no added vit K for 10 weeks. Heart lesions were not found in birds fed any of the experimental diets. Mortality, body weight gain, and prothrombin time did not differ significantly between birds fed the practical diet regardless of vit K supplementation. In contrast, the RS-IS diet significantly increased mortality, prothrombin time, and markedly decreased growth. Furthermore, more than a third of the birds fed the high sugar diet had subcutaneous edema, which resembled exudative diathesis. Compared with swine, poultry are apparently less susceptible to granulomatous endocardial lesions induced by a vit K deficiency.

Exacerbative effect of vitamin A on malabsorption syndrome in chicks.

The interaction between malabsorption syndrome (MAS) and dietary vitamins A and D was studied in broiler chicks reared in floor pens for 4 weeks. The chicks were naturally infected with MAS, whereas hatchmates fed the same diets but in a separate facility (battery brooder) did not exhibit signs of MAS and, therefore, were considered controls. MAS significantly reduced body weights, bone ash, serum calcium and phosphorus concentrations, and liver lipids and increased the incidence of skeletal abnormalities (tibial dyschondroplasia and rickets). Rather than ameliorating the effects of MAS, vitamin A caused a further reduction in body weight and bone ash. A possible nutrient interaction between vitamin A and vitamin D or vitamin E in birds with MAS may account for the exacerbative effect of vitamin A.

Vitamin A toxicity: comparative changes in bone of the broiler and leghorn chicks.

Severe skeletal lesions were produced in both broilers and leghorns orally administered toxic levels of vitamin A (330 or 660 IU vit. A/g body weight X day) for 21 consecutive days. Hypervitaminosis A in broilers produced an osteodystrophy characterized by abnormal thickening of the proliferative-maturation zone, metaphyseal sclerosis, hyperosteoidosis, decreased number of osteoclasts, and parathyroid gland hyperplasia. In leghorns, the osteodystrophic lesions were characterized by a thin proliferative-maturation zone, a relatively thickened hypertrophy zone, flattened spindle-shaped osteoblasts, and osteoporosis. In both broilers and leghorns given excessive vitamin A, the osteogenic layer of periosteum in all bones was thin.

The role of calcium and phosphorus in the etiology of tibial dyschondroplasia in young chicks.

By means of a central composite rotatable design with dietary calcium levels of 0.63, 0.70, 1.10, 1.50 and 1.67% and total phosphorus levels of 0.53, 0.61, 0.81, 1.01 and 1.09%, practical-type rations were fed for 2 weeks to commercial broiler-type chickens. The design involved three replicates for each rotatable point and 15 replicates for the central point with 10 cockerels per replicate or a total of 390 birds. When the experiment was terminated, the chickens were weighted and killed; one tibia was used to determine bone ash and the other tibia for scoring the incidence and severity of tibial dyschondroplasia. The incidence of tibial dyschondroplasia in chickens fed the various diets ranged from 0 to 37%. A high incidence of tibial dyschondroplasia was associated with diets containing high phosphorus and low calcium levels. Tibial dyschondroplasia score and percentage of bone ash were not correlated. No obvious relationships existed between tibial dyschondroplasia incidence and percentage retention of calcium and phosphorus. A second experiment confirmed the finding that increased dietary calcium levels would reduce the incidence of tibial dyschondroplasia when chickens were fed diets high in phosphorus.

The physiological effects of feeding warfarin poultry.

A 20 week study using layer and broiler strain chicks of both sexes was undertaken to determine whether poultry were susceptible to warfarin-induced granulomatous endocardial lesions. Birds were fed a corn-soybean meal basal diet with no added vitamin K, supplemented with either 0, 25, 50, or 100 ppm of warfarin or vitamin K at .6 mg/kg of diet. Broiler chicks showed a higher incidence of hemorrhages, more mortality, and longer prothrombin times than did the layer strain fed the same diets. Regardless of the breed, female chicks fed the highest warfarin level had significantly longer prothrombin times than the male chicks. However, there were no sex differences associated with mortality or incidence of hemorrhages among birds fed the experimental diets. Growth was most significantly reduced for chicks fed the highest warfarin level and to a lesser degree for birds fed 50 ppm of warfarin. In contrast to the first 10 weeks of the study, there was a sharp decline in mortality, incidence of hemorrhages, and prothrombin times during the last 10 weeks of the study. Layer and broiler strains of chickens fed warfarin for 20 weeks showed no evidence of granulomatous endocardial lesions as was reported for swine (Oshiro and Brooks, 1975).

Tibial dyschondroplasia in broilers: comparison to dietary additives and strains.

The effects of broiler strain and various additives to practical corn-soy diets on the incidence of tibial dyschondroplasia (TD) were studied using broiler chicks maintained in battery brooders. At the termination of each experiment, birds were killed and examined for TD by cutting longitudinally along the tibia. No significant difference in the incidence of TD was found among the nine broiler strains compared. While the incidence of twisted legs was higher than TD among the nine strains there was no apparent correlation between the two leg disorders. Studies conducted using the following additives did not significantly increase the incidence of TD in broilers when compared to controls: monensin, sodium chloride, copper sulfate, magnesium sulfate, potassium sulfate, roxarsone, gentian violet, erythromycin, vitamin K, or vitamin D3. However, dietary ammonium chloride (1.5 or 30%) did increase the incidence of TD, whereas adding various fermentation products at levels of 10 and 20% either in the absence or presence of ammonium chloride failed to reduce the incidence of the disease. The incidences of TD among broiler chicks fed high dietary fluoride were nonsignificant; no evidence of the disease was found in Leghorn chicks fed the same diets. Chicks maintained in battery brooders in these studies, generally had a lower incidence of TD than that reported for commercial flocks in the field. Furthermore, manipulation of feed additives or ingredients in practical rations for broiler chickens did not increase the incidence of the disease.

Influence of water deprivation on water consumption, growth, and carcass characteristics of ducks.

Two-week-old White Pekin ducks were granted access to water either 4, 6, 8, 16, or 24 hr per day for a period of 4 weeks. The effects of water deprivation on water consumption, growth parameters, and carcass traits were determined. Compared to all other treatments, ducks allowed access to water for 4 hr per day had significantly lower (P less than .05) water intake, body weight, and feed consumption. Increasing water access time to either 6, 8, or 16 hr per day significantly increased (P less than .05) water consumption. Further significant increases in water consumption were not found when ducks were granted access to water for 24 hr per day. Prediction equations are presented for estimating daily intake of water for each treatment. There were no significant differences in final body weight or total feed consumption among ducks on the 6, 8, and 16 hr treatments. Overall feed conversion did not differ significantly among the treatments. No distinct relationship between length of water deprivation and yield of breast meat were observed. The advantages and disadvantages of limiting commercial ducks access to water for 8 hr per day in order to reduce water consumption are discussed.

Reproduction of the Oily Bird Syndrome in broilers.

The Oily Bird Syndrome (OBS) was successfully reproduced in broilers under laboratory conditions which included elevated temperatures simulating summer conditions and feeding high energy diets with a relatively wide calorie to protein ratio. No significant difference in incidence of the syndrome was detected in broilers fed a corn-soy diet, or one with 13% animal protein concentrates and 7.5% bakery product, or with a diet containing 10% distillers dried gains with solubles. Substituting animal tallow for poultry oil significantly (P less than .05) increased the incidence of the syndrome. Feeding diets with a more narrow calorie to protein ratio significantly reduced incidence in one experiment, and feeding an unpelleted diet from 3 to 7 weeks of age also significantly reduced the incidence below that of birds fed the same diet in pelleted form. Incidence of OBS was significantly less for birds housed in a separate building with lower temperature conditions than those maintained in a house with a higher environmental temperature. The OBS could best be observed under commercial processing conditions. Results of these experiments show that growing broilers at a high environmental temperature and feeding diets with wide calorie to protein ratios provide conditions conducive to the development of OBS. Further studies will be necessary to determine the specific etiology of the syndrome.

Effect of dietary protein and fat levels on fattening of corticosterone-injected broiler chicks.

The effect of dietary composition on fattening of cotricosterone-injected broilers was studied with Hubbard male chicks. Corticosterone was injected daily from 26 days of age during 9 days at a concentration of 600 micrograms/bird/day. Dietary energy to protein (E:P) ratio or fat level did not significantly affect body weight gain, abdominal fat pad size, skin dry matter, or liver parameters in corticosterone-injected chicks. However, corticosterone-injected birds fed the diet containing the narrower E:P ratio had smaller livers which also contained less fat than chicks fed the diet with a wide E:P ratio. This effect, although consistant in three experiments, was significant (P < .01) only in one. It is concluded that dietary fat level and E:P ratio do not affect carcass fat content of corticosterone-injected chicks, but diets containing wide E:P ratios may increase fattening of the liver considerably.

Variations in the incidence of tibial dyschondroplasia associated with different environmental conditions.

Experiments were designed to study environmental factors that affect incidence of tibial dyschondroplasia (TD) in broiler chickens. A significant higher frequency of TD was observed in birds reared in floor pens vs. those maintained in a battery brooder with wire floors and fed the same diet. Incorporating either 5% raw or autoclaved broiler litter in the diet produced no significant effect on the incidence of the disease in chicks reared in floor pens covered with wood shavings or wire frames. During the first six months of 1979, the incidence of TD declined markedly in market-age broilers of the same strain fed similar diets and maintained on litter in the same broiler house.

Effect of corticosterone and prolactin on fattening in broiler chicks.

The influence of temporal interaction of corticosterone and prolactin on fattening in broilers was studied in male chicks subjected to continuous illumination. Injections were started at 26 days of age and each experiment continued for 10 days. Corticosterone, injected daily during nine days at a concentration of 300 or 600 microgram/bird/day significantly (P less than .01) decreased weight gain and increased abdominal fat pad size, skin dry matter, relative liver size, and liver fat content. Corticosterone injected at eight 1600 or 1000 hr elicited essentially the same response. Prolactin, injected daily either at 1600 or 1000 hr during nine days at a concentration of 232 microgram/bird/day, did not significantly affect any of the above parameters. The combination of corticosterone (600 microgram/bird/day for nine days) injected at 1600 hr and prolactin (232 microgram/bird/day) injected simultaneously or 18 hr or 42 hr later, caused a further significant (P less than .05) decrease in weight gain in two out of the three experiments. This combination, however, as well as that of 300 microgram corticosterone/bird/day, had no consistent effect on the parameters of fattening. It is concluded that fattening of chicks induced by injections of corticosterone and prolactin is mainly due to the effect of corticosterone.