In vitro effects of a mixture of Escherichia coli heat-stable enterotoxins (STa and STb) on isolated jejunum of 3-week-old male pigs were studied, using everted intestinal sac techniques. Heat-stable enterotoxins increased chloride secretion and chloride absorption in everted intestinal sacs. The increase of secretory flux was greater than that for absorptive flux. Vasoactive intestinal peptide (6 x 10-9M) increased chloride secretion, but had no effect on chloride absorption. Neither vasoactive intestinal peptide nor pilocarpine (10-5M) had additive effect to ST. Secretory effects of ST were not blocked by atropine 2 x 10-5M), clonidine (10-6M), or morphine (4.2 X 10-6M).

Addition of alanine and taurine blocked killing of lymphocytes caused by culture at 45 C. The optimal concentration for thermoprotection was achieved at 12.5 mM for L-alanine and 5 mM for taurine. Both D and L forms of alanine provided thermoprotection. The effect of these agents was not simply to increase osmolarity of the culture medium, because NaCl did not provide thermoprotection at comparable concentrations. Alanine and taurine were each tested at concentration of 50 mM for ability to block heat shock-induced killing and developmental retardation of 8- to 16-cell mouse embryos. Both agents enhanced embryo development after exposure to high temperature, though development remained less than that for embryos not exposed to high temperature. In one experiment, for example, 81% of embryos cultured at 38 C advanced in development during culture vs 0% at 42 C, 15% at 42 C with alanine, and 32% at 42 C with taurine. The beneficial effect of alanine at high temperature may have been partly attributable to effects independent of thermoprotection, because development of embryos cultured at 38 C was also improved by alanine.

Heat stress is major concern for maintaining optimum production in livestock. The improvement of productivity in dairy animals, exposed to adverse environmental conditions, is primarily focused on improving the microclimate and nutritional management of the animals. The experiment was conducted on three groups of animals comprising six adult buffaloes in each group. Two groups were exposed to heat stress in the psychrometric chamber (40oC), the third group was kept under ambient conditions as control. One of the exposed groups was offered ascorbic acid (20g/day/animal). The blood samples were taken at every 4th day up to 16th day. Samples were analyzed for the total plasma protein and plasma albumin. Results showed that as the days of exposure progressed, the level of stress increased which is evident from the elevated level of total proteins. When compared with the ascorbic acid supplemented group (7.28±0.09 gm/dl), the non-supplemented group had higher protein content (7.93±0.13 gm/dl). There was significant difference (P 0.05) in protein levels among the groups. The level of albumin also followed the same pattern as that of total protein but in heat stressed (2.42±0.17gm/ dl) and ascorbic acid supplemented animals (2.41±0.19 gm/dl), the globulin levels declined as compared to group kept at ambient conditions (2.79±0.33 gm/dl). Further, the Albumin:Globulin ratio was significantly (P 0.05) higher in heat stressed animals (2.78±0.43) and ascorbic acid supplemented animals (2.19±0.30) as compared to control group (1.61±0.37). It can be concluded that ascorbic acid supplementation would be beneficial to buffalo producers of the arid/ semi-arid regions in amelioration of stress challenge imposed by the harsh weather.

Survivability of Listeria monocytogenes in clay loam soil was examined at 30° C for a period of 35 days. The microorganism inoculated in soil steadily declined from 3.5 × 10 6 g -1 to 3.9 × 10 4 g -1 (P = 0.05) on 35 th days. Destruction of normal soil microflora by heat treatment resulted in marginal rise in 3.3 × 10 6 g -1 of L. monocytogenes to 4.2 × 10 6 g -1 during the first 7 days, followed by steady decline to 5.6 × 10 4 g -1 on 35 th days. Heat treated soil inoculated with lower concentration of L. monocytogenes (3.6 × 10 4 g -1 ) supported sharp rise in its population to 4.8 × 10 6 g -1 (P=0.05) during the first weak which gradually declined, but remained higher (6.1 × 10 4 g -1 ) than the initial load even on 35 th days. In non-sterile soil, the rise was less appreciable but L. monocytogenes maintained its levels (10 4 g -1 ) during the experimental period. Survivability of the microorganisms was also observed in the soil with added chicken manure, cattle manure or sheep/goat manure.