Biomedical subjects

C V Maxwell

Publications and source records attributed to C V Maxwell.

49 records · Page 3Linked to original sources

PubMed1983

Effect of dietary fat source and level on the performance of neonatal and early weaned pigs.

The effect of dietary fat source in liquid, semipurified diets was studied with 22 Yorkshire pigs. The four treatment groups were fed diets containing 32% butterfat, corn oil, coconut oil or lard on a dry matter basis. Pigs were delivered by Cesarean section and maintained under pathogen-free conditions. Gain and efficiency of feed use were greater (P less than .05) for pigs fed coconut oil than for pigs fed corn oil or lard. In a second trial, choice white grease was added to a starter diet at levels of 0, 4, 8 and 12%. Individual performance of 68 early-weaned (about 27 d of age) Yorkshire pigs was monitored for 35 d. Levels of corn and soybean meal were altered to maintain a constant ratio of other nutrients to digestible energy. Feed intake decreased as fat level increased (linear effect, P less than .004). Gains the first 2 wk also decreased linearly with fat level (P less than .06). Efficiency of feed use was not significantly affected by dietary fat level, but efficiency of use of calculated digestible energy tended to decrease (P less than .07) with added fat.

Animals↗

PubMed1982

Growth, reproductive performance and nitrogen balance of gilts as affected by protein intake and stage of gestation.

The effects of four levels of crude protein (CP) and stage of gestation on the growth, reproductive performance and N balance of 64 crossbred gilts were examined in two trials. Gilts were fed 147, 256, 309 or 369 g of CP daily in trial 1 and 119, 227, 275 or 326 g/d in trial 2. Total body weight gain and average daily gain (ADG) were not significantly affected by protein intake, although the quadratic effect on ADG approached significance (P less than .1). Both total body weight gain and ADG increased linearly (P less than .01) as stage of gestation progressed. Gilts were slaughtered at 30, 60 or 90 d of gestation and reproductive performance was evaluated. Protein intake did not significantly affect numbers of corpora lutea or live embryos, survival rate or embryo length. But survival rate (P less than .05), number of corpora lutea (P less than .05) and live embryo numbers (P less than .01) declined linearly as gestation stage progressed. Embryo length increased linearly (P less than .05) as stage of gestation progressed. Nitrogen balance studies were conducted before breeding and in early, mid and late gestation. Significant trial x protein level x collection period interactions existed. In trial 1, N retention increased linearly (P less than .01) as dietary protein increased. Retention increased (P less than .01) by 4.1 g/d from prebreeding to early pregnancy. Stage of gestation had a quadratic effect on retained N; retention was higher in early and late gestation than in mid-gestation. In trial 2, mean N retention during pregnancy was -1.7 g/d. Retention was not significantly affected by protein intake but retained N declined quadratically (P less than .05) with stage of gestation to a -16.3 g/d at d 90. In contrast with trial 1, pregnancy did not result in an increase in retention of N. A relationship between protein intake and N balance data and resulting reproductive performance could not be established. The lowest levels of protein intake (147 and 119 g/d in trials 1 and 2, respectively) appeared to be adequate for the first 90 d of gestation in the gilt. However, N retention was not maximized at this protein intake.

Animals↗

PubMed1978

Effect of age and dietary fat level on fatty acid oxidation in the neonatal pig.

A total of 35 pigs were obtained by cesarean section, placed in individual sterile isolators, and randomly allotted to treatment groups. Thirty pigs received purified, isoenergetic liquid diets containing 2 or 32% butterfat (dry matter basis) and were killed at 1, 7, or 21 days of age. Five pigs were killed at 2 hours post delivery and received no diet. Twenty-one-day old pigs showed a tendency for higher weight gain and feed consumption when consuming the 32% fat diet although the differences were not significant. The rate of oxidation of [U-14C]palmitate to CO2 and acid soluble products was measured in homogenates of liver, kidney, heart, and leg muscle (biceps femoris) from pigs 0, 1, 7, and 21 days of age. The relative rates of oxidation of [U-14C]myristate, [U-14C]palmitate, and [U-14C]stearate were measured in homogenates of liver from 7-day old pigs. Palmitate oxidation was stimulated by carnitine in all four tissues and the rate of carnitine-stimulated palmitate oxidation to acid soluble products in heart and to CO2 in liver was higher in tissues from pigs consuming the 32% fat diet. The rate of palmitate oxidation increased with age in liver, kidney and leg muscle tissues and was maximum at 21 days in kidney and leg muscle and at 7 days in liver. The rate of palmitate oxidation in heart tended to decrease with animal age. In homogenates of liver from 7-day old pigs, palmitate was oxidized at a faster rate than stearate or myristate. The activities of carnitine palmitoyltransferase (CPT) (EC 2.3.1a) and succinate dehydrogenase (EC 1.3.99.1) in mitochondria isolated from liver, kidney, heart, and leg muscle did not vary considerably with age although CPT activity tended to be higher in those tissues from pigs consuming the high fat diet. Changes in the rate of palmitate oxidation with age tended to parallel changes in the level of mitochondrial protein per g of wet tissue and suggested an increased ability to utilize fat as an energy substrate during early development of the neonatal pig.

Aging↗

PubMed1977

Effect of dietary fat level on growth and lipogenesis in the colostrum deprived neonatal pig.

Thirty male neonatal pigs were obtained by cesarean section and randomly allotted from littermate groups to three diets containing 2%, 17%, and 32% fat on a dry matter basis. Butterfat was used to replace glucose in the isoenergetic liquid, semipurified diets. Each pig was placed in a sterile isolator and fed ad libitum five times daily. After 14 days, pigs were weighed, killed, and samples of liver and backfat were obtained. The carcass of each pig was ground and samples obtained for determination of total body fat and protein. An increase in the level of dietary fat resulted in a significant increase in 14 day weight gain and a tendency for improved feed efficiency. These results demonstrate not only that the neonatal pig can utilize semipurified liquid diets high in butterfat content, but also that energy from butterfat appears to be used as efficiently as energy from glucose from growth purposes. Increasing dietary fat level decreased the activity of fatty acid synthetase and citrate cleavage enzyme in adipose tissue and liver, and decreased the activity of malic enzyme in adipose tissue. The specific activities of these three enzymes were higher in adipose tissue than in liver.

Animals↗

PubMed1974