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G. L. Rumsey

Publications and source records attributed to G. L. Rumsey.

54 records · Page 3Linked to original sources
USGS1978

Net energy maintenance requirements of salmonids as measured by direct calorimetry: Effect of body size and environmental temperature

Most studies of metabolic rates and energy requirements in aquatic animals have been conducted using indirect methods wherein heat production estimates were based on O 2 consumed and CO 2 produced. The purpose of the present study was to determine the feasibility of direct calorimetry as a method for measuring heat production of fish and to determine the effect of environmental temperature and body size on the metabolic rate of several species. An adiabatic bomb calorimeter was modified to hold living fish and to measure small increments of heat. Heat production of rainbow, brook and lake trout, and Atlantic salmon weighting 1 to 4 g each was measured at temperatures ranging from 3° to 18°. Heat production of rainbow trout having individual body weights from 0.85 to 57.0 g was measured at 15°. Direct calorimetry was found to be a satisfactory method for measuring heat production of fish. Tests were reproducible and could be completed in 6 to 8 hours. The heat production changed linearly with temperature over the range tested. Regression equations for heat production for fish weighing 1 to 4 g were: for rainbow trout, HP = 0.59 + 0.0525T; for Atlantic salmon, HP = 0.66 + 0.0339T; for brook trout, HP = 0.37 + 0.0770T; and for lake trout, HP = 0.41 + 0.0680T where HP is kcal/kg/hr and T is temperature. The effect of size on metabolic rate was linear from 1 to 4 g and proportional to W 0.63 from 4 to 57 g.

Journal of Nutrition↗
USGS1978

Heat increment associated with dietary protein, fat, carbohydrate and complete diets in salmonids: comparative energetic efficiency

The heat increment (HI) of feeding, which is the increased heat production following consumption of food by an animal, accounts for as much as 30% of the ingested metabolizable energy (ME) in mammals and birds. The purpose of these experiments was to measure the HI associated with the feeding of a complete diet and purified fat, protein, and carbohydrate to salmonids. Measured amounts were fed and the heat production was measured by direct calorimetry. Increased heat production was observed about 30 minutes after feeding and remained elevated for 1 to 5 hours, depending on the amount and type of material fed. The HI of protein was much lower with fish than with mammals and amounted to <5% of the ingested ME. The HI's of carbohydrate and protein were not significantly different from each other but both were higher than fat. The HI, when complete diets were fed, was <3% of the ME. The net energy of protein is higher for fish than for birds or mammals. A major part of the superior energetic efficiency of fish is due to the low energy cost of protein metabolism.

Journal of Nutrition↗
USGS1975

Amino acid supplementation of casein in diets of Atlantic salmon (Salmo salar) fry and of soybean meal for rainbow trout (Salmo gairdneri) fingerlings

Fry of Atlantic salmon ( Salmo salar ) fed a diet containing isolated fish protein grew significantly faster than those fed a diet containing casein without supplemental amino acids, and had improved feed conversion and lower mortality. Supplementing the casein diet with essential amino acids to the levels in the isolated fish protein diet significantly increased growth rate, reduced mortality, and improved feed conversion.When fingerling rainbow trout ( S . gairdneri ) were fed diets containing soybean meal as the sole source of protein, additions of amino acids to simulate those levels of essential amino acids in trout eggs and isolated fish protein significantly improved growth. Additions of methionine, lysine, histidine, and leucine individually and in several combinations had no effect.

Journal of the Fisheries Research Board of Canada↗