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Geology topics

G. L. Rumsey

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

At least 37 records · Page 2Linked to original sources
USGS1983

Factors affecting dietary requirement and deficiency signs of L-tryptophan in rainbow trout

Two experiments were conducted to determine the concentration of dietary tryptophan needed for optimal growth and survival of fingerling rainbow trout ( Salmo gairdneri ), to characterize signs of tryptophan deficiency, and to ascertain the effects of niacin on deficiency signs. Test diets containing either hydrolyzed or intact casein were fed with graded levels of added L-tryptophan (0.0, 0.25, 0.50, 0.75 and 1.0 g/100 g protein). Maximum growth occurred at 0.75 and 0.50 g tryptophan in fish fed hydrolyzed and intact casein, respectively. Changes in mineral and amino acid mixtures in the intact casein diet yielded a cation-anion (Na + K - Cl) balance of + 15.3 meq/100 g diet and pH of 6.44, compared with a balance of -21.3 and -25 meq, and pH 5.8 and 4.4 for unmodified hydrolyzed and intact casein diets, respectively. Analysis of growth by the polynomial regression function; Y = 0.16 + 0.429 X - 0.26 X 2 , where Y = mean daily gain in grams, and X = grams of added tryptophan/100 g protein, predicted that at least 0.58 g of tryptophan was needed for maximum weight gain. Analysis of apparent pathology-free fish by the function; Y = 34.33 + 147.33 X = 83.87 X 2 , where Y = percentage with no signs of deficiency, and X = grams of added tryptophan, predicted that 0.63 g tryptophan/100 g protein was needed for optimum health scores. Deletion of supplemental niacin did not affect fish response to tryptophan.

Journal of Nutrition↗
USGS1983

Dietary requirements for essential branched-chain amino acids by lake trout

In a 12‐week growth study of the dietary requirements of young lake trout Salvelinus namaycush for essential branched‐chain amino acids, the leucine requirement was between 2.74 and 3.66%, and the isoleucine requirement between 1.54 and 2.06%, of dietary protein (as‐fed basis). These ranges are substantially lower than those published and widely used in formulation of salmonid feeds. On the basis of both growth criteria and concentration of free amino acids in blood plasma, the valine requirement was within the range of 1.77 to 2.23% of dietary protein. The upper value of this range is substantially lower than the requirement reported for chinook salmon Oncorhynchus tshawytscha. Plasma valine concentrations in lake trout responded to dietary supplements of valine above the requirement level; the concentrations increased sharply once the requirement was exceeded. This finding is similar to observations recorded in other animals.

Transactions of the American Fisheries Society↗
USGS1983

Methionine and cystine requirements of rainbow trout

Methionine and cystine requirements of rainbow trout (Salmo gairdneri) were studied by supplementing a 35% protein semipurified basal diet with these amino acids at graded levels in a factorial design. In experiment 1 (initial average weight of fish, 1.5 g), methionirie levels were 0.30, 0.45, and 0.60% of the diet and cystine levels were 0.04, 0.15, 0.30, 0.45, and 0.60%. In experiment 2 (initial average weight of fish, 8.8 g), methionine levels were 0.55, 0.75, and 0.95% and cystine levels were 0.04, 0.08, 0.12, 0.16, 0.24, and 0.32%. Methionine requirement was estimated to be between 0.55 and 0.75% in the presence of adequate dietary cystine and the cystine requirement was about 0.30% with a diet marginally deficient in methionine. The requirement for both sulfur amino acids was, therefore, between 0.85 and 1.05% of the diet or 2.50 and 3.00% of the protein. Molar efficiency of conversion of dietary methionine to cystine was highest (80%) when the diet was deficient in methionine; this efficiency decreased as levels of dietary methionine increased. Bilateral cataracts occurred in methionine‐deficient but not in cystine‐deficient trout.

Progressive Fish-Culturist↗
USGS1982

Use of ozone in a water reuse system for salmonids

A water reuse system is described in which ozone is used in addition to biological filters to remove toxic metabolic wastes from the water. The system functions at a higher rate of efficiency than has been reported for other reuse systems and supports excellent growth of rainbow trout (Salmo gairdneri).

Progressive Fish-Culturist↗
USGS1981

Riboflavin requirement of fingerling rainbow trout

Fingerling rainbow trout (Salmo gairdneri) were fed purified diets containing graded levels (0, 3, 6, 12, 18, 24, and 54 mg/kg) of supplemental riboflavin for 20 weeks. The cellular riboflavin supply of the fingerlings was estimated on the basis of the activity of the FAD‐dependent enzyme, erythrocyte glutathione reductase (EGR). The dietary riboflavin level that produced the fastest growth, an efficient feed: gain ratio, and normal values for the EGR activity coefficient was about 3 mg of supplemental riboflavin per kilogram of diet.

Progressive Fish-Culturist↗
USGS1981

Dairy-processing wastes as a replacement protein source in diets of rainbow trout

Dairy‐processing wastes, not previously used in domestic animal and fish feeds, were evaluated as a replacement protein source in the diet of rainbow trout (Salmo gairdneri). Dairy residue replaced 10% dried whey without reducing growth or feed efficiency, and feed costs were reduced. Growth and feeding efficiency were somewhat reduced when dairy‐processing wastes in the diet were 15 or 20%.

Progressive Fish-Culturist↗
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↗