Thesis (M.S.)--Oregon State University, 2007-12-20. / Printout. Includes bibliographical references (leaves 121-127). Also available on the World Wide Web.

Forty four first-calf heifers were randomly selected to determine lactational and metabolic responses to high fat diets and isoacids. All heifers were allowed ad libitum consumption of a control diet for the first 2 weeks of lactation and then offered experimental diets Eor the next 4 weeks. Each 6 cows of twenty four were randomly assigned to 1) a control diet (C) with 35.2% corn silage, 14.4% alfalfa haylage and 50.4% concentrate (dry matter basis), 2) C with 2% calcium stearate (S) substituted for corn grain, 3) C with 2% tallow (T) for corn grain, and 4) C with 10% whole cottonseed (W) for corn grain, cottonseed meal and cottonseed hulls. The remaining 20 heifers were randomly assigned to diets C, S, T, and W, each with 4g/kg isoacids added (CI, SI, TI, and WI). Fat supplementation or isoacid addition did not affect milk production. Addition cf isoacid increased milk fat percentage, 4% fat-corrected milk, milk fat production (kg/day) and dry matter intake. Differences due tc isoacid were greatest when added to W. Increased milk lactose percentage and weight gain were evident in animal receiving WI compared to W ration. Fat supplementation depressed percentages cf milk fat, milk lactose and milk solids-not-fat. Milk protein percentage and somatic cell count were not affected by treatments. Plasma glucose,and glucose and epinephrine challenge parameters were not affected by diet. Peak plasma non-esterified fatty acid response to epinephrine injection, detected at 10 to 12 minites, was similar for C, S, T, and W. Concentrations of individual volatile fatty acids (VFA) and total VFA in rumen fluid were increased by fat supplements. Isoacid addition increased the amounts of isobutyrate and isovalerate; however, acetate and total VFA concentrations were decreased compared to CI when isoacids were added to high fat diets. The ratio of acetate to propionate was similar for all diets. Digestibilities cf dry matter, crude protein, and acid detergent fiber were not influenced by diet. The efficiency of energy utilization was highest for control diet. In conclusion, lactational, metabolic, and physiological responses to S, CI, and WI were favorable. Responses to W were lowest. / M.S.

Eighty-six crossbred (Duroc x Yorkshire) gilts were used in two trials (50 gilts in Trial 1 and 36 gilts in Trial 2) for an assessment of the effect of supplemental dietary fat during early gestation on fetal survival, fetal development, and fatty acid concentration in gilt plasma and fetal head and body. Three diets contained 4% (w/w) added fat either as coconut, soybean, or fish (menhaden) oils. A fourth diet was used as a control. On d 37 to 45 postbreeding, gilts were slaughtered and numerous fetal and ovarian measurements made. Two sets of four randomly selected fetuses per gilt from Trial 1 were prepared. Blood samples from each gilt were obtained on the day of slaughter for determination of the plasma fatty acid profile. Across both trials, percentage fetal survival did not differ according to treatment, but in Trial 2 fetal survival was higher (P < .06) for gilts fed fish oil, compared with the controls. The fatty acid profile of plasma of gilts and the conceptus tissues were similar; both were influenced by the fatty acid concentration of the diets. The ratio of n-3/n-6 fatty acids was higher in conceptus tissue than in maternal plasma and the ratio was higher (P < .05) for the fish oil diet compared with the other diets. The relatively high concentration of omega-3 fatty acids in fetal tissues supports the hypothesis that omega-3 fatty acids play a role in the development of the pig conceptus and contributes to improve fetal survival. However, the high percentage fetal survival observed in all the treatments may have masked benefits of supplemental oil. / Master of Science

Master of Science

The objective of this study was to examine the effects of a medium chain triglyceride oil mixture (MCTo), designed to increase energy expenditure and improve lipid profiles containing medium chain triglycerides, phytosterols and n-3 fatty acids in the form of flaxseed oil, versus the antioxidant alpha-lipoic acid (ALA). Forty-eight hamsters were fed (i) hypercholesterol emic (HC) control, (ii) HC MCTo, (iii) HC ALA, (iv) HC MCTo/ALA diets for 4 weeks. No effects on food intake, body weight, total body water, lean body mass, fat mass, and tissue thiobarbituric acid-reactive substances (TBARS) were observed. ALA alone had no effect on total cholesterol (TC); however, MCTo feeding increased TC with (p < 0.03) and without (p < 0.003) ALA when compared to control. ALA increased HDL levels compared to control (p 0.04) and MCTo/ALA (p < 0.007) groups. MCTo, with (p < 0.0001) or without (p < 0.006) ALA, increased non-HDL cholesterol levels versus control. The non-HDL:HDL ratio was decreased by ALA compared to MCTo (45%) and MCTo/ALA (68%) (p < 0.0001), a similar trend was seen when compared to the HC control (22%) group (p < 0.14). Triglyceride levels were not altered by any of the dietary treatments. Liver and heart tissue reduced glutathione (GSH) was increased (p < 0.05) by all three treatments when compared to control. Both tissues showed an increase (p < 0.05) in oxidized glutathione (GSSG) when fed ALA compared to all other treatments. Hamsters fed ALA had a lower (p < 0.05) GSH/GSSG ratio compared to all treatment groups. In conclusion, MCTo feeding does not elicit beneficial effects on circulating plasma lipids and measures of body composition. In addition, our results do not clearly support an improvement in oxidative status through supplementation of ALA. However, our results do support the existence of beneficial effects of ALA on circulating lipoprotein content in the hamster.

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