The effect of adaptation to constant low environmental temperature on water and electrolyte distribution in skeletal muscle and brain has been studied in 2-year-old rainbow trout. Following introduction to 6 °C of trout previously acclimated to 16 °C, measurements were made, at intervals, of plasma Na, K, Cl, Ca, Mg, and phosphate and of brain and muscle Na, K, and Cl. Plasma, muscle, and brain tissue showed a transient but significant drop in water content during the first days of cold exposure. A coincident paradoxical increase in total body weight suggests the possibility of an osmotic withdrawal of body water by the gut contents during this period. Cl space and Cl–K space estimates of muscle extracellular space were not significantly influenced during cold acclimation. Most of the plasma electrolytes measured showed significant transient alterations in concentration.Significant reciprocal changes in brain Na and K concentration were measured shortly after transfer to 6 °C and a large (61%) increase in brain Cl concentration occurred after 3 weeks of cold adaptation.Large, rapid but mostly transient shifts in muscle Na and K occurred. During the first 3 days of cold exposure muscle lost 61% of the Na and 30% of the K present before transfer. This loss is reflected in a rise in plasma Na and K. The possibility that the unusual efflux of intrafiber Na and K together might represent a forced extrusion of positive charge following a temperature-induced intrafiber loss of organic anions or gain of divalent cations is discussed.
We have developed a dilution method for avian urine and modified existing analytical methods for ammonia, urea, uric acid and total nitrogen to permit determination of all these compounds on aliquots of the same urine sample. The proportions of urinary nitrogen in these compounds were: uric acid 55-72%, ammonia 11-21% and urea 2-11%. This ranking of proportions was consistent for four different dietary protein-water availability regimes. There were no significant differences in the proportions of these nitrogenous compounds due to either dietary protein intake or changes in water availability.
Pigmented and depigmented Japanese quail eggs were incubated either in the presence of a light source for one week or in the dark. Acceleration of embryonic development was apparent by the first day of incubation in the depigmented eggs exposed to light. Embryonic weights of eggs exposed to light were significantly (P less than .05) greater than eggs incubated in the dark by the fourth day of incubation. Air cell temperatures of depigmented eggs were significantly (P less than .05) lower than pigmented eggs by the fourth day of incubation when both groups of eggs were exposed to a light source. Thus photoacceleration appeared to be a real effect, and great enough to overcome the lower egg temperature at which these embryos developed. Embryos developing in lighted depigmented eggs can decrease the hatching time of other groups incubated with them.
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