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The study was conducted to ascertain the effects of nutritional restrictions on growth, physiological adaptability and reproduction in sheep. The experiment was conducted for a period of 35 days covering two estrus cycles in 40 adult Malpura ewes. The animals were randomly divided into four groups of 10 animals each (100%; 80%; 70%; 60% of ad libitum). The ewes were fed a ration consisting of 70% roughage and 30% concentrate. At weekly intervals, physiological responses were recorded and blood samples were also collected. Nutritional restriction of different magnitude (80%; 70%; 60% of ad libitum) altered the growth, physiological adaptability and estrus responses to different extents in Malpura ewes. But the impact was most severe in 60% of ad libitum group. Nutritional restriction to the level of 60% of ad libitum feeding significantly decreased body weight, body condition score, plasma insulin-like growth factor, pulse rate in the morning, respiration rate and pulse rate in the afternoon, plasma glucose, total protein, albumin, total cholesterol, plasma tri-iodo-thyronine and thyroxine, plasma Cortisol, plasma estradiol, estrus % and estrus duration, while it significantly increased plasma concentration of growth hormone, hemoglobin, plasma concentration of progesterone and estrus cycle length. The study clearly establishes the effect of different levels of nutrition and its impact on the biological functions necessary to adapt to semi-arid environment. Although, 80%, 70% and 60% groups showed signs of nutritional stress, the effects were more pronounced in 60% ewes. Furthermore, this study clearly establishes the role of various hormones required to adapt to different levels of nutritional stress in Malpura ewes. [ABSTRACT FROM AUTHOR]

The whole‐body residues of Cd and Pb in the tissues of Louisiana swamp crayfish (Procambarus clarkii) were determined by flame AAS technique. Test animals were collected from roadside ditches (18 locations) alongside major highways. The water and soil samples were also collected from the same sites. The mean Cd and Pb concentrations (mg/l) in crayfish tissues were 0.46 and 0.07, respectively. The levels of Cd and Pb in the water were 0.09 and 0.04; and in soil were 2.85 and 0.87 mg/l, respectively. The concentration of cadmium was 32 and Pb 12 times more than in the water. The bioaccumulation factors (BF) for Cd and Pb in crayfish tissues were 5.1 and 1.7, respectively. Alligator weed (Alternanthera philoxiroides) plants were exposed to 0.5 mg/l Cd‐chloride or Pb‐nitrate solutions for 3 wk period, thrice. The mean Pb accumulation in roots was 1.31 mg/l, followed by stem (0.078 mg/l), but Cd only accumulated in root (0.83 mg/l). The BF for Pb and Cd in plant tissues were 14.8 and 16.6, respectively. The uptake of metals was time‐dependent (P = <0.01). These data suggest that although there is no biomagnification of Cd and Pb from alligator weed to crayfish, both metals readily accumulate in field‐collected crayfish and laboratory‐exposed alligator weed. [ABSTRACT FROM PUBLISHER]

The major objective of this work was to assess the possible long‐term effects of ThiodanR insecticide on the growth‐rate, fecundity and hatching potential of Louisiana crayfish, Procambarus clarkii. Adult males and females were collected from an Experiment Station, and were exposed to 600 ppb ThiodanR. Since the aqueous solubility of endosulfan (active ingredient of ThiodanR) is very low, the actual concentration of 2, 10, 15 and 600 ppb ThiodanR in tap water was determined by electron‐capture gas chromatography. The amount of endosulfan I and II in 2 ppb ThiodanR was 0.8 and 0.32 ppb, respectively; 10 ppb = 3.8 and 1.52; 15 ppb =6.3 and 2.52; and 600 ppb = 284 and 113.6 endosulfan I and 11, respectively. Male and female crayfish were exposed to 600 ppb ThiodanR for 20 weeks during which mating occurred. The mean number of eggs produced by control crayfish (N=10) was 288 and by treated crayfish (N=10) was 225, which did not differ significantly. Hatchlings from unexposed crayfish were used to determine the effects of ThiodanR on weight, length and molting frequency. Sixty hatchlings were exposed to 2, 10 and 15 ppb ThiodanR for a period of 9, 23 and 27 weeks during which they achieved a mean weight (gain) of 0.64, 0.19 and 0.17g, respectively. Control hatchlings gained 0.82, 0.30 and 0.19g during the same period. These differences were also insignificant statistically. The length (gain) by these hatchlings (control and treated) over the same time period did not differ significantly. There was a slight increase (insignificant) in the molting frequencies of treated hatchlings. Comparative data on the chronic effects of ThiodanR for crayfish are not available. Based on the reported LC50 values for grass shrimp, mysid shrimp and Korean shrimp, we conclude that Louisiana crayfish, P. clarkii is more tolerant to this insecticide than the ocher decapod crustaceans. [ABSTRACT FROM PUBLISHER]

The bioaccumulation potential of endosulfan was determined by constantly exposing male and female adult crayfish, Procambarus clarkii to 100 ppb ThiodanR insecticide for 8 wks. The crayfish were removed at 2 wk intervals and the uptake by tissues (whole‐body) was determined by electron capture gas‐chromatography. The same number of pre‐exposed crayfish (100 ppb ThiodanR) were transferred to endosulfan‐free water after 8 wks, and insecticide loss (depuration) was similarly guantitated. The maximum amount of insecticide and its metabolites detected after 8 wks were 197 ppb endosulfan II, 18 ppb endosulfan I and 3 ppb endosulfan sulfate. During the first 4 wks of depuration, endosulfan loss from crayfish tissues occurred rapidly, and only 3 ppb endosulfan I remained. No endosulfan II and sulfate were detected beyond 4 wks. The residues in male vs female were not significant statistically. Bioaccumulation factor (BF) for endosulfan II for crayfish tissues was 1.97, which is considerably lower than for other aquatic invertebrates (26 for scallop, Chlamys opercularis and 600 for mussel, Mytilus edulis. The presence of endosulfan sulfate in the tissues cannot be considered as ‘detoxification’ which is as toxic as the parent compound. [ABSTRACT FROM PUBLISHER]