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150 results on '"Lovell, Richard T."'

3. Dietary folate requirement determined for channel catfish, Ictalurus punctatus

Author

Duncan, Patricia L., Lovell, Richard T., Butterworth, C.E., Jr., Freeberg, Larry E., and Tamura T.

Subjects
Folic acid in animal nutrition -- Research, Channel catfish -- Food and nutrition, Nutrition -- Requirements, Food/cooking/nutrition
Abstract

Juvenile channel catfish, Ictalurus punctatus, were fed semipurified basal diets containing 0, 0.2, 0.5, 1.0, 4.0 or 10.0 mg/kg of folic acid or 10 g/kg of succinylsulfathiazole in aquaria for 15 wk. Fish fed the sulfonamide showed higher mortality, lower weight gain, lower thrombocyte counts, higher hemocytoblast and neutrophil counts, and lower liver folate concentrations than did control fish (0 folic acid), indicating that significant intestinal bacterial synthesis of folate occurs in channel catfish. There were positive quadratic regressions of weight gain, hematocrit, erythrocyte and leukocyte numbers, and positive linear regressions of plasma and liver folate on dietary folic acid concentrations. Broken-line analysis showed that the dietary requirements for folic acid for optimum weight gain, hematocrit, and erythrocyte and leukocyte numbers were 1.01, 1.17, 1.12 and 1.15 mg/kg, respectively. Plasma and liver concentrations of folate associated with normal growth and hematopoiesis were 22.9 nmol/L and 20.0 nmol/g, respectively. Ratios of leukocytes and lymphocytes to erythrocytes were maximal in fish fed 4.0 mg folic acid/kg, indicating that immunocompetence may increase as the dietary dose exceeds that required for normal growth. Anemia in folate-deficient channel catfish was characterized by pale livers, spleens, gills and kidneys, and by poikilocytosis, anisocytosis, pyknosis, cytoplasmic clearing, increased numbers of hemocytoblasts, macrocytosis, and binucleated erythrocytes or 'spectacle' cells.

Published
1993

4. Dietary nutrient allowances for fish

Author

Lovell, Richard T.

Subjects
Fishes -- Food and nutrition, Animal nutrition -- Requirements, Agricultural industry, Business
Abstract

The National Research Council's Dec. 1993 edition of 'Nutrient Requirements of Fish' recommends similar nutritional allowances for commercially valuable marine and freshwater fish species. Unlike warmblooded animals, fish have lower dietary energy requirement because of lower heat increment and body temperature maintenance requirement. This low-energy requirement calls for a high-protein diet because fish need less energy for maintenance and synthesis of nitrogen-excretion products.

Published
1996

5. Dietary nutrient allowances for fish

Author

Lovell, Richard T.

Subjects
Fishes -- Food and nutrition, Animal feeding and feeds -- Composition, Animal nutrition -- Requirements, Agricultural industry, Business
Abstract

The nutrient requirements of channel catfish, rainbow trout, Pacific salmon, common carp and tilapia are presented. The values provided are based on the 1993 edition of the National Research Council's 'Nutrient Requirements of Fish' publication and represent minimum requirements for ensuring maximum fish performance. Since nutrient requirements do not vary much between fish species, these recommendations can also be applied to other fishes, although only to a limited extent. Feed managers are urged to include surpluses to compensate for losses due to environmental effects, processing and storage.

Published
1995

11. 13 Diet and Fish Husbandry: 13.5 Penaeid Shrimp.

Author

Lovell, Richard T.

Abstract

Chapter 13.5 of the book "Fish and Nutrition" is presented. It provides information on penaeid shrimp culture, its breeding methods and nutrient requirements. Shrimps need also ten essential amino acids as do finfish and terrestrial animals. Information is also offered on the feeding and feed practices for shrimps which are found to feed on aquatic organisms.

Published
2002

12. 13 Diet and Fish Husbandry: 13.4 Tilapias.

Author

Lovell, Richard T.

Abstract

Chapter 13.4 of the book "Fish Nutrition" is presented. It describes tilapia culture, its breeding practices and nutrient requirements. Information on feeds and feeding requirements is offered, citing that some species of tilapias feed on natural plant food such as phytoplankton, zooplankton and plant leaves.

Published
2002

13. 13 Diet and Fish Husbandry: 13.3 Salmonids.

Author

Lovell, Richard T.

Abstract

Chapter 13.3 of the book "Fish and Nutrition" is presented. It describes salmonid aquaculture, the growth of the industry worldwide and culture methods. Information is also offered on feeding methods and practices for salmonid fry and salmon for release including the nutrient requirements and feed formulations.

Published
2002

14. 13 Diet and Fish Husbandry: 13.1 Introduction.

Author

Lovell, Richard T.

Abstract

Chapter 13.1 of the book "Fish and Nutrition" is presented. It discusses commercial aquaculture, the nutrient needs of fish and the level of intervention in aquaculture environment. Information on fish culture where food comes from natural aquatic food sources, with supplementation from prepared feeds and on highly modified environments is provided. It also compares feeding fish from feeding land animals.

Published
2002

15. 13 Diet and Fish Husbandry: 13.2 Channel Catfish.

Author

Lovell, Richard T.

Abstract

Chapter 13.2 of the book "Fish and Nutrition" is presented. It describes channel catfish culture, the industry and its characteristics. In the U.S., catfish farming is said to be a major industry principally on the Mississippi River flood plain. Information on feeding practices for catfish fry, fingerling and production is offered including winter feeding and feeding of diseased catfish.

Published
2002

17. Energy requirement of fish lower than farm animals

Author

Lovell, Richard T.

Subjects
Fishes -- Food and nutrition, Protein metabolism -- Analysis, Agricultural industry, Business
Abstract

Fish require less energy for protein synthesis compared to warm-blooded farm animals. Fish expend less energy to maintain their posture and to move about in water and therefore have a considerably lower need for dietary energy. In addition, They use less energy in protein metabolsim since their nitrogenous wastes are excreted mostly in the form of ammonia and not urea or uric acid. In view of this, it would be more beneficial for fish to be fed with diets with higher protein concentrations.

Published
1993

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