Call number: LD2668 .T4 1954 B8 / Master of Science

Three studies were conducted to evaluate the relationship between insulin and nutritional parameters in rainbow trout. In the first study effects on growth parameters and tissue composition of rainbow trout were investigated following injection of bovine insulin at two dose levels every 48 hr for 56 days. In addition, [¹⁴C]-leucine incorporation into plasma, liver, and skeletal muscle was studied for the two insulin treatments and a group of the saline-injected controls given a single shock-dose of insulin (5.0 IU/kg). Hypoglycemic responses were observed with all insulin treatments. In comparison to controls, high insulin treatment gave a significant body weight increase. At both levels, insulin increased the content of protein, lipid, and also the incorporation of [¹⁴C]-leucine activity in skeletal muscle. Simultaneous decreases in specific activity of plasma and liver tissue indicated a net movement of [¹⁴C]-leucine toward the peripheral musculature. No effect of the hormone was seen on the glycogen content of liver or muscle tissue over the 56-day period. In a second study, the effect of bovine insulin on tissue incorporation of [¹⁴C]-glucose and [³H]-leucine was investigated in fed and fasted rainbow trout reared on a control and high-protein diet. Insulin produced marked hypoglycemia and mobilization of liver glycogen in all treatments. Although insulin gave no evidence of glycogenic stimulation it did appear to promote oxidative clearance of [¹⁴C]-glucose. Compared to [¹⁴C]-glucose much greater tissue incorporation of [³H]-leucine was observed in fasted fish; insulin stimulated the incorporation of [³H]-leucine into skeletal muscle protein. In plasma, liver, and skeletal muscle of all treatments, the summed specific activities of [³H]-leucine was considerably greater than that of the summed values of [¹⁴C]-glucose following insulin administration. Four weeks of fasting apparently lowered basal metabolism but no changes were observed in plasma glucose and glycogen stores. There was some evidence of gluconeogenic activity in the high protein-fasted fish and the data indicated in all fasted treatments a stimulation of [¹⁴C]-glucose and [³H]-leucine metabolism following insulin administration. As a third investigation, [¹²⁵I]-iodoinsulin binding studies in the presence of a concentration range of bovine insulin were conducted to establish specific insulin binding levels in erythrocytes, skeletal muscle plasma membranes and isolated hepatocytes of rainbow trout reared on control-, high-protein and high-carbohydrate diets. Negative cooperativity was observed and receptor concentrations and apparent dissociation constants established for each preparation. No differences of specific binding attributed to diet were detected in either erythrocytes or skeletal muscle plasma membrane preparations, However, the receptor concentration of isolated hepatocytes from high-carbohydrate reared trout was increased. This contrasted to comparable mammalian studies. In view of an apparent depression of receptor concentration in skeletal muscle plasma membranes and isolated hepatocytes of high-protein reared trout, these data were interpreted according to the reciprocal relationship observed between endogenous insulin and insulin receptor concentrations established for mammals. Unlike mammals where glucose was shown to be the primary insulin secretagogue, endogenous insulin levels in rainbow trout have been closely correlated to circulatory amino acids and are thought to be primarily controlled by these protein metabolites. / Graduation date: 1982

Dietary fiber has been suggested as interfering with mineral utilization. The influence of broccoli florets and wastes, cauliflower heads and wastes, wheat bran and Metamucil on mineral uptake by the rat was determined using balance studies. All results were compared to control animals fed diets containing 10% hydrolyzed cellulose. Utilization of Ca, Mg, Cu, Zn and Fe were determined to be 62, 33, 23, 42, and 52% respectively for control animals. The uptake of Mg, Zn and Fe were significantly reduced to 12, 16 and 18% respectively from broccoli florets. Broccoli wastes decreased absorption of Zn to 14% and created a negative iron balance. Cauliflower heads improved Zn assimilation to 61%. Cauliflower wastes depressed Ca absorption to 26% and caused Mg balance to be negative. Wheat bran improved utilization of Ca and Zn to 88 and 54% respectively. Metamucil increased uptake of Ca to 88% and Mg to 53%. Copper balance was unaffected by any test diet. To better understand results of balance trials, the bioavailability of Fe from some sources was measured. The relative biological values (RBV) of endogenous Fe in broccoli, cauliflower, Brussel sprouts and wheat bran were determined to be 93, 88, 83, 98% respectively. These values were obtained using rats fed control diets containing 5% hydrolyzed cellulose and ferrous sulfate (RBV = 100). The efficiency - true bioavailability of utilizing dietary Fe is approximately one-half of the RBV. These values agree well with apparent uptake of iron by animals in the balance trials for all diets except broccoli. This exception may be due to differences in the amount and source of broccoli fed. High dietary levels of broccoli florets and wastes appear to interfere with utilization of Fe and Zn. Cauliflower wastes depress absorption of Ca and Mg. With the exceptions noted, dietary fiber from plant sources does not appear to decrease the utilization of minerals by the rat. The nature of mineral complexes in plants may be more important in defining the degree of its absorption. / Graduation date: 1980

Methods for assessing vitamin A status in the horse and rabbit were developed and evaluated using a modified Relative Dose Response Test (%RDR = A₄-A₀/A₄ X 100, where A₄ and A₀ represent four hours post-feeding and fasting serum total vitamin A levels, respectively) for horses and a Vitamin A Fractionation (VAF) Test monitoring serum levels of vitamin A palmitate, vitamin A acetate and retinol for horses and rabbits. In Experiment 1 (RDR test), 5 horses per treatment group were fed 0 (deficient), 10,000 (control) or 80,000 (excess) I.U. vitamin A palmitate daily, for 30 days. RDR Test was positive (>20%) for all horses receiving diets deficient in vitamin A and negative «20%) for all horses receiving control or excess diets. In Experiment 2 (VAF test), rabbits were fed varying dietary levels of vitamin A palmitate (ranging from 0 to 58000 I.U./kg feed) for up to 87 days. Percentages of retinol and vitamin A palmitate were reflective of vitamin A status. An approaching vita'min A deficiency or toxicity is indicated when percentages of vitamin A palmitate and retinol are more than 1 SD from the means observed for control rabbits (6.2±1.8 and 92.9±3.5, respectively). If a deficiency is approaching then percentage of vitamin A palmitate will be between 21% and 73% and percentage retinol between 8% and 21%. If toxicity is approaching then percentage vitamin A palmitate and retinol will be greater than 21% and less than 73%. Rabbit is normal if percentages are maintained within the ± SD of the mean. Experiment 3 (VAF test) was conducted using the same horses and conditions as in Experiment 1. After 30 days on treatment, percentages of retinol and vitamin A palmitate were significantly lower and higher (P<.05) than controls, for deficient and excess horses, respectively. The percentages of vitamin A palmitate and retinol in deficient horses were intermediate between values observed in horses from the other two treatment groups. If percentage retinol is between 45% and 65% and percentage vitamin A palmitate is between 31% and 45% the horse is approaching deficiency. If the percentage retinol is less than 45% and and vitamin A palmitate is greater than 45%, then the horse is probably approaching toxicity. Results suggests that both RDR and VAF tests can be used to determine vitamin A status before appearance of overt signs of deficiency occur, however only the VAF test is suitable for detecting toxicity.

Experiments were conducted to determine the effects of sorghum grain flake density on site and extent of nutrient digestion in beef steers. Sorghum grain was steam-flaked to densities of .41, .36, .31 and .26 kg/L. Diet digestibility was determined during the growing and finishing periods of a feedlot performance trial with dietary grain levels of 50 and 80%, respectively. Starch digestion was increased from 92 to 98%, and from 98 to 99%, on growing and finishing diets, respectively, in response to decreased flake density. Digestion of dry matter and energy was increased in growing diets but decreased in finishing diets as flake density in the diets decreased. Fiber digestion was not influenced in growing diets but decreased in finishing diets. In an experiment using cannulated steers fed diets with 50% grain, flow of starch at the duodenum was reduced 50% (466 vs 232 g/d) as flake density was decreased from .41 to .26 kg/L. Starch digestion was increased in each segment of the digestive tract with the greatest response occurring in the rumen (83 vs 92%, for .41 and .26 kg/L, respectively). In another experiment using cannulated steers fed 80% grain diets, starch flow from the rumen was also reduced by 50% (694 vs 371 g/d) by decreasing flake density from .41 to .36 kg/I. Starch digestion was improved throughout the digestive tract. Ruminal, intestinal and total tract starch digestion was comparable when grain was flaked to .36 kg/s or less. In conclusion, flaking of sorghum grain over a range of flake densities primarily affected starch digestion. As flake density in the diet decreased, starch digestion increased in all three studies. The largest differences among treatments in ruminal, intestinal and total tract digestion occurred between the .41 and .36 kg/L treatments. Starch digestion was similar when sorghum grain was flaked to .36, .31 or .26 kg/L. Response pattern for protein digestion followed that for starch digestibility. Effect of flake density on digestion of other nutrients was not consistent among the three experiments.

Experiments were conducted to compare the effect of processing grain sorghum either by dry rolling or steam flaking on the performance and metabolism of high producing dairy cow. In an 80 d trial, following a 14 d pretrial for covariance adjustments, 36 Holstein cows divided in 4 groups were fed a total mixed ration (37 forage:63 concentrate) prepared with one of the following four grains: Steam-rolled corn (CORN), dry-rolled sorghum (DRS), steam-flaked sorghum (SFS) and an equal mixture of DRS and SFS (MIX). Grain comprised 42.2% of diet DM. In the last 14 d of the experimental period a digestibility trial was conducted. There was no difference (PS < .05) in milk, FCM or milk fat production across treatments. Because cows on SFS consumed less DM (P < .05) than those on MIX, the gross efficiency of FCM production was higher, (P < .05) for SFS. Other treatments were intermediate for DM intake and FCM efficiency. Milk protein percentage and production were higher (P < .05) for SFS compared to DRS, while lactose and SNF were higher (P < .05) for SFS compared to DRS, while lactose and SNF percentages were the highest (P < .05) for SFS compared to other diets. Apparent digestibility of starch from SFS was the highest (P < .01) and that from DRS was the lowest while apparent digestibility of the fiber components and of CP were lower (P < .05) for SFS compared to DRS. Improvement in FCM efficiency and milk protein production was probably due to increased starch degradability. In a second experiment, the same diets used in the lactation trial were fed to 4 duodenally cannulated cows in a 4 x 4 Latin square design. Total tract digestibility of starch was higher (P < .05) for SFS than MIX and DRS diets and tended to be more digested in the rumen than starch from other diets. Cows fed SFS also tended to more efficiently convert dietary CP digested in the rumen to BCP and to have higher BCP flow to the duodenum. Cows on the SFS diet had highest (P < .01) fecal pH, tended to have the lowest amount of fecal protein and the highest apparent digestion of N.

Lactating Holstein cows were used to evaluate the contribution of recycled urea nitrogen to bacterial protein exiting the rumen, and appearing in milk and feces during continuous jugular infusion of ¹⁵N-labelled urea in long-term infusion (72 h) and short term infusion (3, 12, 20, and 24 h) studies. Two cows in the first trial, and four cows in the second trial fitted with T-type duodenal cannulae were fed either a high grain or high forage diet. Urea labeled with ¹⁵N was infused continuously into the jugular vein for 72 h in trial 1 and for 3, 12, 20, and 24 h in trial 2. Cr₂O₃ was used as a digestibility marker. In trial 1, duodenal digesta, feces and urine were sampled every 4 h for 5 d (during 72 h of infusion and 48 h thereafter). Milk and blood were sampled every 12 h for 5 d, and total urine was collected for 5 d. In trial 2, duodenal digesta and urine were sampled every 6 h for 3 d. Feces, milk and blood were sampled every 12 h for 3 d, and total urine was collected for 3 d. Percent of total N in digesta and bacteria entering the duodenum which originated from recycled N was greater in cows fed high grain than high forage, 20 vs 10%, P < .23 and 28 vs 15%, P < .18 respectively, for trial 1. In both trials, ¹⁵N enrichment of digesta and bacteria entering the duodenum was higher for high grain from shortly after the beginning until the end of infusion periods of more than 20 h. Enrichment patterns of urine (and blood) were inverse of those in digesta and bacteria, reflecting a greater recycling of urea on the high grain diet. Flow of N from the rumen to the small intestine was higher on high grain than on high forage in both trials, (128 vs 107% of N intake for trial 1, and 123 vs 98% of N intake for trial 2), which was consistent with the larger amount of recycled N on high grain. Urinary excretion of ¹⁵N accounted for about 84% of that excreted in trial 1, and 76% in trial 2; whereas, feces and milk accounted for a total of 16% in trial 1, and 24% in trial 2. Percent of ¹⁵N infused which was retained in the body 2 d after infusion ceased was 23% in tiral 1, and 17% at 72 h in trial 2. It was estimated by the ¹⁵N ratio techniques that 64 to 74% of the total N passing into the duodenum was bacterial N in trial 1. In conclusion, these data demonstrate that about twice as much endogenous N is recycled and incorporated into bacterial N on a high grain than a high forage diet fed to lactating cows. The higher N passage into the duodenum than N intake on a high grain diet might be explained by more N being recycled into the rumen.

Three experiments were conducted to evaluate the effects of a fat-supplemented diet on the horse. Experiment one examined the effect of a diet which contained 20% digestible energy as corn oil fed to four horses in comparison with a control group. Plasma lipoproteins, muscle lipoprotein lipase, total serum lipids, and ultrasound-estimated body fat were monitored for 10 weeks. The plasma lipoproteins fractionated into VLDL, LDL, HDL and albumin, and each was assayed for protein, cholesterol and triglyceride content. Results indicated that the fat-fed horses increased in LDL and HDL protein, VLDL triglyceride, and LDL and HDL cholesterol content. There was a slight increase in total serum lipids while body fat was unchanged. In experiment two, two horses were fed the same fat diet and two horses served as controls. Total serum lipids and plasma lipoproteins were analyzed from samples obtained during a post-prandial sampling period at 2, 4, and 6 weeks of the trial. Results indicated an adaptation by the fat-fed horses to the added dietary fat through an increase in lipoprotein protein content, suggesting larger quantities of the lipoprotein fractions. LDL and HDL cholesterol levels also increased. Finally, VLDL triglyceride levels increased in the fat-supplemented horses reflecting the increased absorption and availability for utilization of the added dietary fat. Experiment three examined the effect of a fat-supplemented diet on exercising horses. All seven horses were fed the high fat diet, and four of them were exercised. A standard exercise test was administered at the start and end of the trial to assess the conditioning program. Total serum lipids, plasma lipoproteins and percent body fat were monitored at weeks 3 and 6 of the trial. Blood samples were collected as in experiment two. The exercised horses exhibited lower VLDL and LDL triglyceride levels as well as lower LDL cholesterol levels. These data suggest that exercise increased the utilization of dietary fat for exercise in the horse, and could subsequently be used as a high-energy feed source in these animals.

Select antibacterials were evaluated for their potential as shrimp aquaculture drugs. Difloxacin and sarafloxacin were evaluated for palatability, toxocity, and residues with respect to shrimp, after 15 days of feeding medicated diets. The pharmacokinetics and bioavailabilities of sulphadimethoxine (SDM) and ormetoprim (OMP) were also established for shrimp. Reductions (p < 0.05) in difloxacin feed palatability were noted as a function of dose. Total survival and mean survival time (p < 0.05) decreased as a function of dose. Signs of animal stress, i.e., lethargic behavior, was also noted in the highest dose group. Shrimp tissue levels of difloxacin were inconclusive and not readily determined with the current analytical methods for the drug in shrimp. However, indications were that elimination may be rapid, i.e., tissue t1/2 of 11.4 h with peak tissue levels following a standard dose response. Feed palatability was reduced (p < 0.05) as a function of sarafloxacin dose. Lower weight gains in the higher dose groups were also noted. Neither the total survival nor the mean survival time (p < 0.05) were affected by sarafloxacin dose. Feed Conversion Ratio's increased with dose, indicating possible subchronic toxicity. Sarafloxacin elimination was rapid, with a tissue t1/2 of 13.4 h and tissue levels decreased to below detectable limits by day 14 of withdrawal in all treatments. Peak tissue levels followed a standard dose response. The hemolymph concentrations versus time data for both SDM and OMP were fitted well by two compartment models. The SDM:OMP parameter estimates of CLs, Vss, and terminal phase t1/2 were 194:2045 ml/kg*h, 1735:25,442 ml/kg, and 6.9:11.5 h, respectively. Plasma protein binding of SDM and OMP was 5.2% and 12.1%, respectively. The bioavailabilities of SDM:OMP were 30:38%. Peak hemolymph concentration (Cmax) and time (Tmax) of SDM post of single oral dose (210 mg/kg) was 14 ug/ml at 4 h, while OMP (42 mg/kg) Cmax and Tmax was 0.45 ug/ml at 0.67 h. The amount of the available oral dose 2 h post administration of SDM:OMP in the hemolymph, muscle, and hepatopancreas were 6.0:0.5%, 9.3:2.8%, and 2.9:20.2%, respectively. Hemolymph and muscle tissue levels were below detectable limits post 48h for SDM and 24 h for OMP.

Digitized by Kansas Correctional Industries