Fatty haemorrhagic liver syndrome in laying hens on diets supplemented with rapeseed products.

Livers of laying hens of Hy-Line No 934E on low erucic acid rapeseed meals and rapeseed oil were studied. Gross lesions in the livers of hens on experimental diets were moderate to severe fatty degeneration, focal necrosis and moderate to severe haemorrhage. Histological examination revealed oedematous foci and lysis of hepatocytes along with large amounts of lipid droplets in the necrotic lesions. Necrotic lesions were not always associated with large haemorrhages. Connective tissue infiltration of older degenerative and haemorrhagic lesions was not extensive. Abdominal haemorrhage from livers occurred when extensive necrosis in the form of hepatocyte lysis and some vascular changes were present, suggesting hepatocytic degeneration caused by toxic products or their metabolites present in rapeseed by-products.     

Wheat root distribution,water extraction pattern and grain yield as influenced by time and rate of irrigation

The effect of first irrigation (26, 40 and 54 days after seeding) and the rate of irrigation (5.5, 7.5 and 9.5 cm) applied subsequently at $\text{IW}\text{E}{}_{\mathrm{<mtext>pan</mtext>}}$ ratio of 0.9 on wheat root distribution, water extraction pattern and grain yield was studied on a barrier-free, sandy loam soil. The crop developed a more extensive root system when the first irrigation was applied after 26 days than after 40 and 54 days. With the first irrigation on the 26th day, the crop, receiving subsequent irrigations less frequently but at a heavier rate, developed a deeper root system than the crop receiving frequent, light irrigations. The water extraction pattern corresponded with the root distribution pattern. A relatively small difference in root density in the deeper layers caused a greater difference in soil water content than in the upper layers. Light and frequent irrigations produced maximum grain yields. However, for developing an extensive root system and enhancing water utilization in the subsoil, an early, light irrigation with subsequent irrigations applied less frequently at a relatively heavier rate seems desirable.     

Histopathologic and electron microscopic studies on the acute toxicity of ochratoxin A in rats

Ochratoxin A was given by gavage to male rats. Moribund and dead animals were necropsied, and the surviving rats, including the controls, were killed 48 hours after dosing. Many of the principal rats were moribund, or began dying, within 12 to 24 hours after dosing. Lesions suggestive of disseminated intravascular coagulation were seen by light microscopy as early as 12 hours after dosing; fibrin deposits were in the spleen, brain choroid plexus, glomerular capillaries, liver, and heart. Renal tubular nephrosis, hepatic and lymphoid necrosis, and necrotic enteritis with villous atrophy were also seen. Electron microscopy demonstrated fibrin strands mixed with degranulated platelets, necrotic leukocytes, and swollen endothelial cells in glomerular capillaries. Myocardial changes included focal supercontracted sarcomeres adjacent to intercalated disks. Swollen sarcolemma, lysed myofibrils and fragmented Z-bands with interstitial edema, vascular thrombosis, and endothelial damage were also seen. The acute pathologic changes induced by ochratoxin A in the intestine, liver, and lymphoid tissues were more obvious than the tubular nephrosis, and the development of a disseminated intravascular coagulation-like syndrome with myocardial changes was a complicating factor.     

Ultrastructural alterations in the kidneys of Pekin ducks fed methylmercury.

Ultrastructural alterations in the kidneys of Pekin ducks were studied after subchronic exposure to methylmercury chloride. Twenty-four male and twenty-four female Pekin ducks, 12 weeks of age were fed 0.0 (control), 0.5, 5.0 and 15.0 parts per million of MeHgCl, mixed in a mash diet for 12 weeks. Birds were observed for clinical signs daily. Kidneys were fixed in situ by perfusion with 4% glutaraldehyde in 0.05 M phosphate buffer and routinely processed for electron microscopy. Only minor morphological changes were observed in the renal corpuscle of ducks in the 0.5 ppm group. The component cells of the renal corpuscle in the 5.0 and 15.0 ppm groups showed several ultrastructural alterations, including an increase in number and size of lysosomes and vacuoles in podocytes and mild vacuolation in mesangial cells. The juxtaglomerular cells of afferent arterioles had crystallized granules. No significant changes were observed in glomerular basement membrane thickness and width of podocyte pedicels. The proximal tubules of the 5.0 and 15.0 ppm groups showed some microvillar loss and an increase in the number and size of lipid droplets, vacuoles and lysosomal bodies. The distal tubular changes in the 5.0 and 15 ppm groups included electron lucency and vacuolation of cytoplasm as well as occasional mitochondrial swelling. The collecting ducts of 5.0 ppm and 15.0 ppm groups showed varying degrees of degenerative changes in both mucus secretory as well as absorptive cells. These results suggest that subchronic exposure of Pekin ducks to methylmercury chloride causes subtle ultrastructural changes in renal corpuscle and marked ultrastructural changes in proximal tubules and collecting ducts.     

Evaluation of indices for identification of pearl millet cultivars adapted to stress and non-stress conditions

Pearl millet (Pennisetum glaucum) is cultivated across a wide range of environments ranging from extremely stressful to favourable. The objective of this research was to compare methods to identify productive cultivars for stress and non-stress conditions. Thirty pearl millet cultivars were evaluated at 22 locations that were grouped as stress, non-stress, or intermediate environments. Five selection indices viz., arithmetic mean (AM), geometric mean (GM), AM (standard units), stress susceptibility index (S) and drought response index (DRI) were calculated for each genotype to determine correlation between selection indices and yield under stress (Y_S), non-stress (Y_NS), and average conditions (Y_AV). Both cultivars and locations were significant sources of variation. Phenology of cultivars had different influence on yielding ability in contrasting environments. While earliness was advantageous for stress conditions, cultivars with longer duration tended to yield more under non-stress conditions. Y_S was only moderately determined by Y_NS. Both AM and GM were suitable indices for selection of cultivars that would perform well across stress, non-stress, and intermediate environments. Stress susceptibility index (S) was negatively correlated with Y_S (r=−0.62^**) but should only be used as a selection criterion in combination with yield under stress (Y_S) to identify cultivars adapted to stress environments. DRI was positively correlated with Y_S but had no association with Y_NS. Results indicated that DRI might be useful for identifying cultivars with high performance under stress particularly when days to flower differ considerably among test entries.     

Uptake and bioconcentration of dieldrin,dimethoate, and permethrin by Tetrahymena pyriformis

A ciliate protozoan, Tetrahymenapyriformis was exposed to three insecticides, dieldrin, dimethoate, and permethrin for 12 hr to study the uptake and bioconcentration potential. Ciliates concentrated 922, 3547, and 1056 gg g^?1 dry wt. over an initial concentration of 1 gg mL^?1 of dieldrin, dimethoate, and permethrin, respectively. The highest bioconcentration factor for three insecticides was 2095, 3547, and 1110, respectively. It is suggested that if levels in the environment reach 1 gg mL^?1 the chief effects would be reduction of cell population, and accumulation of the toxicants by ciliates. Accumulation of insecticides by ciliates would permit the toxicants to enter aquatic food chains. Thus the compounds could exert toxic effects at higher trophic levels.     

In vitro direct plant regeneration and Agrobacterium‐mediated transformation of lucerne (Medicago sativa L.)

In vitro direct plant regeneration of lucerne was achieved by simultaneous application of thidiazuron (TDZ) and 6‐benzyladenine (BA) in Murashige and Skoog (MS) medium. Seedlings were germinated and grown for 6 d on growth regulator–containing MS medium. The shoot tip, consisting of the apical meristem along with parts of the cotyledonary leaves and hypocotyl, was then cultured on a medium containing the growth regulator(s). Adventitious budding of the shoot tip was promoted synergistically by treatment with TDZ and BA, and a maximum of thirty‐five shoots per explant was obtained on a medium supplemented with 2 mg L^?1 TDZ and 1 mg L^?1 BA. Plant regeneration frequency varied from 67 to 93%, and five Indian lucerne cultivars responded well to the regeneration protocol. The Agrobacterium‐mediated transformation frequency from co‐cultivated explants was 13% following multiple shoot induction. Southern analysis of the T₀ plants and T₁ progenies confirmed stable inheritance of the hpt marker gene. Agrobacterium infection of the explant caused a significant reduction in the plant regeneration frequency (23%) and the number of shoots induced (11) when compared with uninfected explants. A single shoot tip provided sufficient material to regenerate and establish twenty‐seven lucerne plants, whereas only nine plants could be regenerated from an Agrobacterium co‐cultivated explant. This transformation protocol could represent a valuable improvement over existing ones for lucerne.     

Influence of duration of aeration on growth and survival of carp fingerlings during high density seed rearing

Impact of varied durations of aeration on growth, survival and production performances of catla (Catla catla), rohu (Labeo rohita), fringe lipped carp (Labeo fimbriatus) and olive barb (Puntius sarana) were evaluated in outdoor concrete tanks (10 m × 5 m × 1.3 m) during fingerlings rearing. At a combined stocking density of 0.5 million fry/ha, provision of night time aeration for 4, 8 and 12 h was evaluated as the three treatments, T-I, T-II and T-III, respectively against control (T-c, without aeration). Overall survival and net biomass of the species increased among the treatments significantly as a function of aeration hours (T-c < T-I < T-II < T-III). Aeration for 8 and 12 h showed significantly higher survival, harvested body weight and SGR in all the carps than those with 4 h (T-I) and no aeration (T-c), suggesting 8–12 h of aeration requirement for fingerlings rearing at such high density. Further, no significant difference between survival levels in T-II and T-III groups suggested 8 h of aeration to be adequate. However, while species-wise performance showed 8–12 h night time aeration to be advantageous for catla and rohu, aeration for 4 h was adequate for fringe lipped carp and olive barb.