Influence of dietary protein and sex on walking ability and bone parameters of broilers

1. The study was conducted to investigate the effect of dietary protein on the walking ability and bone parameters of broilers reared under summer temperatures which ranged from 26 to 32C(+/-2C). 2. Three different dietary protein combinations were used. The diets (per kg) were: low protein with 205 g crude protein and 12.94 MJ ME, 184 g crude protein and 12.75 MJ ME; medium protein with 219 g crude protein and 12.99 MJ ME, 201 g crude protein and 12.87 MJ ME; and high protein with 238 g crude protein and 12.99 MJ ME, 216 g crude protein and 12.96 MJ ME from 0 to 4 and 4 to 7 weeks of age, respectively. Body weights of birds were recorded and birds' walking ability (gait scoring) were scored for each bird, according to 3 categories (completely normal to immobile, at 4 and 7 weeks). Tibia parameters and tibia plateau angles were also determined at 7 weeks. 3. Birds fed on the low protein were lighter than those fed on the medium or high protein diets. At 7 weeks, birds with poor walking ability weighed 149 g less than birds with no walking difficulty. 4. Bone parameters were not affected by dietary protein, sex or gait score. There was a significantly positive correlation between bone strength and radiographic density. Bone strength was also significantly correlated with bone weight and length.     

Grass Yields Under Clipping and Watering Explain Varied Efficacy of Management Intensive Grazing on Rangelands

Management intensive grazing (MIG) may not maximize plant productivity on rangelands because of morphophysiological traits of grassland vegetation. We examined defoliation and moisture effects on the biomass yield of rhizomatous and caespitose grass pairs that were either phylogenetically similar or of similar agroclimatic adaptation, including two agronomic grasses. From relatively low to high moisture regime adaptation, species pairs included western wheatgrass (Pascopyrum smithii [Rydb.] A. Love) and needle-and-thread (Hesperostipa comata [Trin. & Rupr.] Barkw.), northern wheatgrass (Elymus lanceolatus [Scribn. & J.G. Sm.]) and western porcupine grass (H. curtiseta [Hitchc.] Barkw.), plains and foothills rough fescue (Festuca hallii [Vasey] and F. campestris Rydb.), and smooth and meadow brome (Bromus inermis Leyss. and B. riparius Rehm). Response variables were shoot yield, root-shoot ratio, and water-use efficiency. We hypothesized that caespitose grasses, regardless of their origin or adaptation to agroclimate regime, would respond more determinately in biomass accumulation. Defoliation effects on shoot biomass were more pronounced under high moisture. Low intensity ? high frequency defoliation yielded similarly to deferred controls in all grasses, and the same was true for high-intensity ? low-frequency (HILF) defoliation in 1 rhizomatous grass. Three of the 4 rhizomatous grasses and 1 caespitose grass yielded greater under HILF defoliation compared with high-intensity ? high-frequency defoliation. Caespitose grasses allocated more biomass to roots under low moisture conditions. Water-use efficiency decreased under high moisture conditions and more intense and/or frequent defoliation and peaked in agronomic grasses. Overall, our results suggested that growth patterns corresponded more with phylogenetic similarity as opposed to growth form. A conceptual model from these results showed that across all species, only the introduced bromes generated greater biomass under HILF defoliation, and this may explain why past research consistently concludes that MIG does not enhance plant productivity on rangelands.     

Sulphadimidine metabolism in vitro: I. sex differences in acetylation and hydroxylation in cultured rat hepatocytes

The hydroxylation and acetylation of 0.5 mM sulphadimidine (SDD) was studied in primary cultures of hepatocytes from male and female rats, and from castrated male and sham operated male rats. In addition, SDD metabolism was investigated in hepatocytes from castrated male rats treated with testosterone, prior to liver cell isolation. In male rat hepatocytes a significantly higher hydroxylation activity was observed than in hepatocytes from female and castrated male rats. Acetylation activity was higher in females. Testosterone induced hydroxylation but did not affect acetylation. These results correlate well with data from previous in vivo studies, showing the relevance of this in vitro model.     

Pathogenesis of Trypanosoma (brucei) evansi in small East African goats

Trypanosoma evansi is the cause of surra, a camel disease which is the most important single cause of economic losses in camel rearing areas. Sheep and goats herded with camels are the most likely hosts for T evansi. Upon intravenous infections goats developed erratic parasitaemia, lost weight and their packed cell volume dropped significantly (P<0–001). Trypanosomes were demonstrated by direct microscopy in extravascular locations such as synovial, peritoneal and cerebrospinal fluids and also in lymph by subinoculations into mice. The carcases were emaciated and pale. Histologically there was lymphatic tissue hyperplasia, muscular atrophy and nephrotic changes. Two animals had necrotic foci in the liver, kidneys, lymph nodes, spleen and lungs and also bronchopneumonia. Histologically there was depopulation of lymphocytes in lymphatic tissues, destruction of hepatocytes in the liver with infiltration by inflammatory cells in the liver, lymph nodes, spleen and the kidneys.