Ultrastructural study of the liver and kidney in ochratoxicosis A in young broiler chicks

Ultrastructural changes are reported in the kidney and liver of 20-day-old broiler chicks fed ochratoxin A (OA), incorporated in the diet at levels of 2 and 4 ppm. Changes in the kidney included the presence of abnormally shaped mitochondria in the proximal convoluted tubules. There was an increase in the size and number of mitochondrial dense granules and cytoplasmic peroxisomes. Intranuclear and cytoplasmic lipid droplets and electron dense round bodies in the dilated smooth endoplasmic reticulum were also noted. Regional thickening and degeneration of the glomerular basement membrane was observed in some cases. In the liver from OA fed birds there was an increased accumulation of cytoplasmic glycogen in the hepatocytes. Abnormal mitochondrial ring forms in the kidney and the accumulation of glycogen in the liver are considered to be of diagnostic significance in ochratoxicosis of young broiler chicks. The severity of the changes was found to be dose related. These results suggest that the mitochondria in the proximal convoluted tubules of kidney were most sensitive to OA toxicity.     

Ultrastructural study of ochratoxicosis in quail (Coturnix coturnix japonica)

Ultrathin sections of liver and kidney from 11-week-old quail fed, from day-old, ochratoxin A (OA) (mixed in the diet at levels of 4 and 8 ppm) were examined in the electron microscope. Pathological changes in the kidneys were limited to the proximal convoluted tubules (PCT) and glomeruli. In the PCTs, abnormal mitochondria and excessive numbers of lipid droplets were the principal findings with glomeruli showing thickened basement membranes. Swollen mitochondria and variable glycogen deposition were the chief features present in the livers. It is suggested that OA is more hepatotoxic in quail than in broilers, as well as being nephrotoxic.     

Effect of level of protein and supplemental choline on reproductive performance of gilts fed sorghum diets

A total of 214 gilts was used (two trials) to determine the effect of protein level and choline supplementation during gestation on weight gain, conception rate and subsequent reproductive performance. The gilts were fed either a 12 or 16% crude protein sorghum-soybean meal diet containing either a high supplemental choline level or no supplemental choline in a 2 X 2 factorial arrangement of treatments. Conception rate was not influenced by either protein or choline level. Choline supplementation increased pig weight at 42 d of age (P less than .14) and litter weight at 21 (P less than .12) and 42 d (P less than .1). Gilts fed the 16% protein diet produced larger pigs at 42 d (P less than .13) and heavier litters at birth, (P less than .1) 21 d (P less than .14) and 42 d (P less than .05) than gilts fed the 12% protein diet. A larger choline effect on litter size and pig and litter weight was observed for gilts fed the 12% protein diet than for those fed the 16% gestation diet, although the protein-choline interaction was not significant for any traits measured. The incidence of spraddle leg condition was low and was not affected by level of dietary protein or supplemental choline.     

Ultrastructural demonstration of mitochondrial calcium overload in myocardial cells from broiler chickens with ascites and induced hypoxia

Two groups of young broiler chickens, namely, naturally occurring field cases of ascites and those with an induced hypoxia, were used in an ultrastructural study to examine the localisation and distribution of intracellular Ca²⁺ in cardiomyocytes. Age-matched healthy flockmates were used to control each group. Deposits of Ca²⁺ were located extensively in the mitochondria, sarcoplasmic reticulum and Golgi apparatus and sometimes in the myocyte and endothelial cell nuclei of both groups of birds. The results suggest that the cells from the hearts of the ascitic broilers may have been exposed to hypoxia since a large proportion of control material showed no Ca²⁺ activity in either mitochondria or nuclei. The presence of a Ca²⁺ overload in the mitochondria of cardiomyocytes from ascitic birds reared at low altitude or sea level suggests that these broilers were suffering from the deleterious effects of chronic hypoxia due to poor or reduced oxygen use.     

Effects of additional feed during late gestation on reproductive performance of sows: a cooperative study

A cooperative research study involving 1,080 litters was conducted at eight stations to determine the effects of additional feed during the last 23 d of gestation on reproductive performance of sows and on preweaning performance of their pigs. Primiparous and multiparous sows were fed fortified corn- or sorghum-soybean meal diets (14% crude protein). Control sows received 1.82 kg/d from March through November and 2.27 kg/d from December through February. Treated sows were fed an additional 1.36 kg of feed/d from d 90 of gestation to farrowing. Sows were allowed to consume the same diet ad libitum during a 21-d lactation. Additional feed in late gestation resulted in greater (P less than .001) sow weight gain from d 90 to d 110 of gestation (16.8 vs 9.0 kg) and greater (P less than .001) parturition-lactation weight loss (21.3 vs 16.4 kg). Total weight gain from breeding to 21 d of lactation favored sows that received extra feed (27.5 vs 22.7 kg; P less than .001). Sows receiving extra feed had more live pigs at farrowing (10.05 vs 9.71, P = .06) and at 21 d postpartum (8.35 vs 8.06, P = .09), and the pigs were heavier at birth (1.48 vs 1.44 kg, P = .003) and at 21 d (5.37 vs 5.20 kg, P = .006). Lactation feed intake and number of days from weaning to estrus were not affected by treatment. The results indicate that additional feed in late gestation improves reproductive performance in sows. In this study, the cost of an additional 31 kg of feed/sow was more than offset by the value of the additional sow weight gain (approximately 5 kg), the additional .3 of a pig/litter at weaning and the additional 2.6 kg of total litter weaning weight.     

Probable occurrence of IgE in the adult domestic fowl (Gallus domesticus) after horse serum stimulation

Radioimmunosorbent techniques using antisera to human immunoglobulin E (IgE) showed the presence of high levels (up to 15,840 U/ml) of IgE in serum and plásma from fowls immunised by repeated intraperitoneal injections of horse serum. These results were confirmed by passive cutaneous anaphylaxis and heat lability tests.     

A conceptual approach to the modelling of herbage intake by hill sheep

A modelling approach is examined as a method of investigating alternative management strategies for improved systems of hill sheep production. In order to take account of the wide range in the quality of hill herbage and the ability of the hill sheep to select preferred components, herbage has been conceptually classified in terms of its digestibility; the digestibility classes are then grazed selectively by sheep. The model deals with herbage growth and deterioration, diet selection and the maintenance and liveweight change of wether sheep. Results produced by the model, in which wethers grazed Agrostis-Festuca at two stocking rates, are discussed.