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PubMed1985

Effect of the beta-adrenergic agonist cimaterol (CL 263,780) on the growth and carcass characteristics of finishing swine.

A randomized complete-block design was used to evaluate the effects of the beta-adrenergic agonist, cimaterol (CL 263,780), on growth rate, feed efficiency and carcass composition of finishing swine. The drug was fed at four levels (0, .25, .5 and 1.0 ppm) to a total of 240 pigs from 64.5 to 103.7 kg live weight. Growth rate and feed efficiency were measured during the 7-wk feeding trial. Feeding cimaterol depressed feed intake, improved feed efficiency and did not alter rate of gain. Carcass evaluation showed that pigs continuously fed cimaterol had 13.2, 9.3 and 9.2% less fat measured at the 10th rib, P2 and average backfat (BF) locations, respectively, compared with controls. Cimaterol-fed pigs had increased loin eye areas (10.9%), and increased semitendinosus (11.8%) and biceps femoris (8.9%) weights compared with controls. The semitendinosus muscles of the cimaterol-fed pigs had less fat and the femur bones were shorter and lighter weight than controls. There were no detected differences in structural soundness of the live pigs, but postmortem evaluation of the hooves indicated that pigs fed 1.0 ppm cimaterol had a higher incidence of hoof lesions. Pigs withdrawn from cimaterol for 7 d were comparable in performance and carcass characteristics with those continuously fed the drug except that carcass fat measurements had generally returned to control values. The data indicate that cimaterol improved the feed efficiency of finishing pigs and increased the lean:fat ratio of their carcasses. Withdrawal of cimaterol caused compensatory fat deposition.

Adipose Tissue↗

PubMed2002

Effect of corn processing on degradable intake protein requirement of finishing cattle.

Three finishing trials were conducted to determine effect of corn processing on degradable intake protein requirement (DIP) of feedlot cattle. In Trial 1, 252 steers were fed 90% concentrate, high-moisture corn-based diets that contained 0, 0.4, 0.8, or 1.2% urea (DM basis) to provide dietary DIP values of 7.0, 8.2, 9.3, and 10.5% of DM, respectively. Nonlinear analysis predicted maximal feed efficiency at 10.2% dietary DIP (95% confidence interval was 9.9 to 13.3%). In Trial 2, 264 steers were fed 90% concentrate, steam-flaked corn-based diets that contained 0, 0.4, 0.8, 1.2, 1.6, or 2.0% urea (DM basis) to provide dietary DIP values of 4.7, 5.8, 7.0, 8.2, 9.3, and 10.5% of DM, respectively. Nonlinear analysis predicted maximal feed efficiency at 7.1% dietary DIP (95% confidence interval was 7.0 to 7.2%). In Trial 3, 90 individually-fed steers were fed 90% concentrate, dry-rolled, high-moisture, or steam-flaked corn-based diets. Urea was factored across diets at 0, 0.5, 1.0, or 2.0% of DM to provide dietary DIP values of 4.8. 6.3, 7.8, 9.2, and 10.7% for dry-rolled, 6.7,8.1,9.6, 11.1, and 12.5% for high-moisture, and 4.7, 6.1, 7.6, 9.0, and 10.5% for steam-flaked corn-based diets, respectively. For the dry-rolled corn-based diet, nonlinear analysis could not predict a requirement because feed efficiency was not improved beyond the first increment of dietary DIP, suggesting that the DIP requirement was met at 6.3% of DM. For the high-moisture corn-based diet, nonlinear analysis predicted maximal feed efficiency at 10.0% dietary DIP (95% confidence interval was 9.2 to 11.3%). For the steam-flaked corn based diet, nonlinear analysis predicted maximal feed efficiency at 9.5% dietary DIP (95% confidence interval was 9.2 to 9.5%). Our estimate of the DIP requirement for dry-rolled corn-based diets (6.3%) agrees well with past research and predicted values. Our estimate of the DIP requirement for high-moisture corn-based diets (10.1%) was very consistent between trials and higher than predicted. Our estimates of the DIP requirement for steam-flaked corn-based diets varied from 7.1 to 9.5%, with an average of 8.3% of dietary DM.

Animal Feed↗

PubMed2006

Effects of growth hormone-releasing factor on growth hormone response, growth and feed conversion efficiency in buffalo heifers (Bubalus bubalis).

The aim of this study was to determine the benefits of growth hormone-releasing factor (GRF) on growth and feed conversion efficiency (FCE) in buffaloes. Twelve Murrah buffalo heifers (Bubalus bubalis) of mean age 24.8 months and mean body weight 302.4kg were divided into two groups (treatment and control) with six animals in each group. The buffaloes were given intravenous injections of bovine GRF (bGRF) at a dose rate of 10microg/100kg body weight or an equal volume of saline at 15-day intervals for a period of 9 months. Plasma growth hormone (GH) responses to bGRF challenge were measured in blood samples collected at 90-day intervals on days 1, 90, 180 and 270 and samples were taken at -60, -30, 0, +10, +20, +30, +60, +120 and +180min relative to bGRF injection. Blood samples were also collected weekly by jugular venepuncture for the quantification of plasma GH. The average growth rate (AGR) and FCE of all animals were recorded at 15-day intervals. Plasma GH concentrations increased (P=0.001) steadily following bGRF challenge, peaking 10-20min after challenge and declining to baseline by 180min. In the treatment group, there were no significant differences (P>0.05) in either the peak heights of the GH response or the area under the curve (AUC) of the GH response after bGRF challenge on any of the four occasions of intensive bleeding. There were overall increases in plasma GH concentrations (P<0.01), AGR (P<0.01) and FCE (P=0.05) in the treatment group compared with the control animals. The study showed that GH responsiveness to administration of bGRF at 15-day intervals over 9 months of treatment remained unchanged in buffalo heifers. Exogenous bGRF treatment for a long period can therefore enhance GH release leading to higher growth rates and better feed conversion efficiency in buffalo heifers.

Animals↗

PubMed1997

Dietary arginine requirement of juvenile yellow perch.

We conducted an 8-wk feeding experiment to determine the dietary arginine requirement of juvenile yellow perch (Perca flavescens). The basal diet contained 33 g crude protein/100 g diet (23 g crude protein supplied by crystalline L-amino acids and 10 g crude protein supplied by casein and gelatin). Eight dietary treatments contained graded levels of L-arginine-HCl ranging from 0.44 to 1.84 g/100 g dry diet in gradations of 0.2 g/100 g diet. Diets were made isonitrogenous with L-glutamic acid and were fed to triplicate groups of fish with an initial weight of 11 g/fish. Dietary arginine significantly affected weight gain and feed efficiency but not survival. The best weight gain and feed efficiency values were 155. 3% increase from initial weight and 0.63, respectively. Quadratic regression analyses of weight gain and feed efficiency data indicated the dietary arginine requirement to be 1.61 and 1.41 g/100 g diet, respectively. We recommend 1.41 g L-arginine-HCl/100 g diet for juvenile yellow perch fed purified diets. The recently developed dietary arginine requirements of fish are surprisingly similar and generally higher than those of the ureotelic mammals and lower than the uricotelic birds.

Amino Acids, Essential↗

PubMed1994

Effects of restricted feeding of growing steers on performance, carcass characteristics, and composition.

Two experiments were conducted to determine the effects of restricted feeding on performance, carcass characteristics, and composition. In Trial 1, 36 individually penned steer calves (280 +/- 13 kg BW) were fed all-concentrate diets at intake levels of ad libitum and 90 and 80% of ad libitum. Trial 2 used 36 individually penned steer calves (298 +/- 14 kg BW) fed corn silage-based growing diets for 84 d followed by 91% concentrate finishing diets. Intakes were as described for Trial 1. Compared with steers with ad libitum intake, ADG was reduced (P < .005) .15 and .25 kg for steers fed 90 and 80% of ad libitum intake, respectively, in Trial 1. In Trial 2, growing phase ADG was reduced (P < .005) .15 and .24 kg for the 90 and 80% of ad libitum feed intake, respectively. Finishing phase ADG was reduced (P < .005) .12 and .21 kg for the 90 and 80% of ad libitum intake, respectively. Feed efficiency was not affected by intake when all-concentrate diets were fed in Trial 1, or when a corn silage-based diet was fed in the growing phase of Trial 2. During the finishing phase of Trial 2, feed efficiency was increased when intake was restricted. Carcass quality grade and 12th rib backfat were reduced (P < .04) with decreases in daily feed intake when all-concentrate diets were fed. However, no effect on carcass characteristics was observed in Trial 2. Liver and heart weights were not affected by daily feed intake. Serum triiodothyronine (T3) concentrations tended (P = .11) to decrease for cattle receiving restricted intakes of all-concentrate diets and were decreased (P < .04) with intake restriction in Trial 2. Carcass fat content was reduced (P < .02), whereas carcass protein and water were increased (P < .06) with reductions in daily feed intake in both trials. We concluded that restrictedly feeding growing-finishing steer calves does not decrease feed efficiency and actually may improve feed efficiency. Restrictedly fed steers had reduced maintenance requirements, and lean tissue accretion represented a greater percentage of their total gain.

Animal Feed↗

PubMed1984

Digestible energy and efficiency of feed utilization in rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Treatment of male rats (300 to 325 g) with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, 15 or 50 micrograms/kg) caused dose-dependent reductions in body weight, feed and water intakes, and fecal output. Urine output, however, was not altered by TCDD. Fecal energy loss, as a percentage of daily feed energy intake (kcal/day), was similar in control and TCDD-treated rats as was the percentage of feed energy absorbed by the gastrointestinal tract, i.e., digestible energy. These findings dispel the long-standing proposal that a gross malabsorption syndrome is responsible for weight loss in TCDD-treated rats and place greater emphasis on hypophagia as the reason for weight loss. In support of a central role for hypophagia, it was found that control rats pair-fed to rats treated with a sublethal dose of TCDD (15 micrograms/kg) lost almost the same amount of weight. However, from 15 to 50 days post-treatment, the pair-fed animals consistently maintained their weight at a 10- to 15-g higher level than age-matched TCDD-treated rats. To determine why this weight difference occurs, the efficiency of feed utilization from Day 30 to 45 post-treatment in ad libitum fed control and TCDD-treated rats (15 micrograms/kg) that were maintaining different levels of body weight was compared. First, daily feed intakes of TCDD-treated and control rats were determined from Day 25 to 30 post-treatment. Second, weights of both groups were lowered by reducing feed intake in two successive 5-day periods to 50 and 10% of the respective ad libitum level. Third, on Days 40 to 45, both groups were refed their prereduction level of intake but reduced in proportion to the intervening loss in metabolic tissue mass. At each level of feed energy reduction, weight losses observed in the TCDD-treated and control rats were equivalent. Furthermore, although given only prerestriction amounts of feed that were indexed to their reduced metabolic body size (body wt kg 0.75), both TCDD-treated and control rats gained weight rapidly and at similar rates during the refeeding period. Thus, rats treated with a sublethal dose of TCDD displayed normal efficiency of feed utilization but did so at a subnormal level of weight. That is, just like control rats, TCDD-treated rats increased their efficiency of feed utilization (weight gain/feed intake) but only when their body weight was caused to fall below the lower weight maintenance level determined by the TCDD dose administered.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1977

Parasitism (Trichostrongylus colubriformis and Eimeria ninakohlyakimovae) in sheep: relationship between wool fiber diameter changes and feed conversion efficiency.

Twenty-five lambs, 5 months of age, were used to compare the infection pressure of Trichostrongylus colubriformis with that of Eimeria ninakohlyakimovae. Effects of the parasitic infection pressure were assayed by determining body weight gains, feed conversion efficiencies, and wool fiber diameter changes (reflecting changes in protein metabolism) in lambs fed a good ration and those given a marginal diet (dehydrated alfalfa pellets). Significant differences in weight grains or feed conversion efficiencies of nematode- or coccidia-infected lambs and noninfected controls were not found, but significant differences due to the parasites' effect on wool fiber diameters and in lamb response to different feeds were found. Protein uptake or assimilation, or both, were apparently affected by a combination of infection with E ninakohlyakimovae and a marginal diet.

Animal Feed↗

PubMed1987

Evaluation of two commercial broiler male lines differing in efficiency of feed utilization.

Factors potentially influencing feed conversion were studied in two lines of broilers known to differ in efficiency of feed utilization. When fed diets differing in energy, line by diet interactions were seldom significant and line effects were greater than those between diets. Chicks from the more efficient line had less plumage cover, less fat, and spent more time sitting than those from the less efficient line. These data imply that improved feed conversion is a function of several traits.

Animal Nutritional Physiological Phenomena↗

PubMed1987

Influence of zinc on growth, somatomedin, and glycosaminoglycan metabolism in rats.

Weanling male rats were fed control ad libitum, zinc-deficient (ZD, 1 ppm zinc) or pair-fed (PF) control diets for 13 days. Rats subsequently were refed control diets for up to 8 days and serially killed. ZD and PF diets significantly decreased growth rate, feed intake, and feed efficiency compared to controls. Body weight and feed efficiency, but not feed intake, were significantly less in ZD compared to PF. Bone zinc was 315, 286, and 109 micrograms/g (p less than 0.0001) for control, PF, and ZD at the end of depletion. 35SO4 uptake by glycosaminoglycans (GAG) was significantly less in ZD compared to either control ad libitum or PF rats. Xylosyltransferase activity was decreased significantly below PF and control by ZD, suggesting depressed enzyme activity and/or decreased GAG acceptor sites. Bioassayable somatomedin (Sm) activity was 0.81, 0.42 and 0.33 +/- 0.09 relative activity for control, PF and ZD at the end of depletion. Sm was statistically less in ZD compared to PF at day 2 and 5 of refeeding, but not at the end of depletion. Sm activity and GAG metabolism returned to normal after refeeding for 2-5 days in PF and for 5-8 days in ZD rats. Serum insulin but not glucose was significantly depressed by ZD and PF diets. Thus, zinc deficiency depressed growth and cartilage metabolism and was associated with decreased Sm activity and insulin levels. Some of these changes could be attributed to decreased feed intake as a result of ZD.

Aging↗

PubMed1993

Research note: fructose feeding increases lower gut weights in germ-free and conventional chicks.

The present study was conducted to investigate whether there was any effect of carbohydrate sources on the magnitude of differences in growth and tissue weights found between germ-free and conventional environments in the chicken. Germ-free and conventional birds were allowed free access to a purified diet in which glucose or fructose was used as a sole carbohydrate source from 7 to 17 days of age. Growth performance and visceral weights were measured at the end of the experiment. The results indicated that there was no difference in growth, feed intake, or feed efficiency between the two environments, but that feeding fructose increased feed intake and decreased feed efficiency compared with feeding glucose. The conventional birds had heavier visceral organ weights including liver, jejuno-ileum, and cecum than did the germ-free counterparts. Feeding fructose resulted in lighter liver weight and heavier weights of jejuno-ileum and cecum than feeding glucose. It was concluded that consuming fructose might increase the lower gut weight of the chicken, as was found by the association with normal microflora, but might not affect overall growth compared with consuming glucose.

Analysis of Variance↗

PubMed1992

Influence of dietary taurine on performance and fat retention in broilers and turkey poults fed varying levels of fat.

Taurine, an amino acid synthesized from Met, primarily functions in bile acid conjugation. Four experiments were conducted to determine whether Tau supplementation of broiler cockerels and female turkey poults to 3 wk of age would influence performance and fat retention at different levels of dietary fat. In these experiments, Tau was added at 0 or .8% to a corn and soybean meal basal diet with dietary poultry fat added at 0, 5, or 10%. Taurine did not affect BW gain of broiler cockerels; however, in one experiment feed efficiency was improved (P less than .01) during the 1st wk and fat retention was improved (P less than .06) at 7 days of age. In experiments with turkey poults, dietary Tau did not affect weight gain but improved feed efficiency (P less than .01) during the 1st wk and decreased overall feed efficiency (P less than .01) in one experiment. Improvement of fat retention by Tau at 14 days was significant (P less than .02) in one experiment and approached significance (P less than .07) in the other experiment. Fat supplementation of both the broiler and turkey diets significantly (P less than .05) improved weight gain, feed efficiency, and fat retention. Supplementary Tau appears to have little effect on performance of broilers and turkeys.

Animal Feed↗

PubMed1987

Genetic association between nest building and brown adipose tissue thermogenesis in female house mice.

Mice selectively bred for either high or low levels of thermoregulatory nest building were cold-acclimated (5 degrees C) for 3 weeks without nesting material; then body weight and food intake were measured. The mice selected for low nest building (Lows) of both sexes showed lower feed efficiencies than the high nest-building mice (Highs), although their body weights were not significantly different (Table 1). This adds to a large body of evidence which suggests that nest building and feed efficiency were influenced by a common mechanism (Lacy et al. 1978; Sulzbach and Lynch 1984; Lynch et al. 1981; Lynch and Roberts 1984). Brown adipose tissue mitochondrial GDP binding and cytochrome c oxidase activity were measured in the above mice. In females, the Lows had 100% higher levels of total GDP binding than the Highs, while no difference between the lines was seen in males. Thus in the High females, lower energy expenditure through brown fat thermogenesis may account for their greater feed efficiency. In males, the genetic differences in feed efficiency must be due to differences in either thermogenesis in tissues other than brown fat, or mechanisms which reduce heat loss.

Adipose Tissue, Brown↗

PubMed1997

Responses of meat-type chickens to choice feeding of diets differing in protein and energy from hatch to market weight.

Chickens from three genetic stocks known to differ in growth potential consumed ad libitum either a single (control) diet or a choice of two diets that differed in protein and energy. Formulation of the choice diets was such that when mixed in specific proportions they provided single diets that decreased in protein and increased in energy over the experimental period. When comparisons of feeding regimens were made at a common age, body weights and feed efficiencies for all stocks were enhanced in chicks fed a single diet. When comparisons were made at a common body weight for controls, chickens fed the single diet were about 15% heavier than those given a dietary choice. For feed efficiency, however, the pattern remained for the faster growing stock whereas there was no difference between feeding regimens for the slower growing stock. Chicks provided a choice of diets had heavier abdominal fat pads and lighter breasts relative to body weight than those fed a single diet. With choice feeding, there were stock by diet interactions for dietary preferences through the first 9 d after hatch. Early on, the interactions resulted from the faster growing stocks exhibiting a greater preference for the diet higher in protein and lower in energy than the slower growing stock. By Day 5, however, the interaction occurred because stocks exhibited either no dietary preference or preferred the diet that was lower in protein and higher in energy. Regardless of genetic stock, at 9 d of age and thereafter there was a clear preference for the diet lower in protein and higher in energy than the diet higher in protein and lower in energy. These data for feed intake were consistent with behavioral observations that showed a preponderance of chicks eating from the feeder containing the diet lower in protein and higher in energy. Compared to a single diet, under choice feeding, energy utilization was negatively influenced more in the faster than slower growing stocks. Protein and sulfur amino acid utilization was not affected by feeding regimen in faster growing stocks, but was enhanced under choice feeding in the slower growing stock. Although lysine utilization was enhanced by choice feeding in all stocks, the effect was greater in the slower than in the faster growing ones. These data demonstrate that although broiler diets are formulated to enhance growth and overall feed efficiency, chicks that are provided a dietary choice of protein and energy do not eat to maximize growth or feed efficiency.

Aging↗

PubMed1986

A genetic analysis of feed conversion efficiency and associated traits in swine.

Performance records were analyzed for 1,869 purebred Duroc and Yorkshire gilts tested in littermate groups of two to four pigs in 703 pens. Traits studied were average daily gain during a standard test period from 56 d of age to 90.7 kg (ADG), average daily feed consumption during the test period (ADF), average backfat thickness (ABF) measured from polaroid photos of ultrasonic scans at 90.7 kg and efficiency of feed conversion for the whole test period (feed conversion efficiency, FCE). The main objectives were: 1) to estimate pertinent genetic and phenotypic parameters and 2) to discuss applications of the findings to the swine industry in the United States. A balanced 16% crude protein diet in pelleted form was provided ad libitum during the entire test period. Nested analyses of variance were computed with both the individual and pen mean records. Sire components of variance and covariance, adjusted for level of inbreeding, were used to estimate heritabilities and genetic and phenotypic variances, covariances and correlations. Heritabilities estimated from individual records were .098 for ADG and .423 for ABF. Estimates from pen means were .105 for ADF and .061 for FCE. Genetic correlations of FCE with ADG, ADF and ABF were estimated as -.520, -.520 and .694, respectively, while phenotypic correlations for the same traits were -.240, .570 and .212, respectively, all from pen means. Genetic and phenotypic correlations of ADG with ABF from individual records were .176 and .254, respectively. Implications for swine testing programs were discussed, including a proposal that would include FCE indirectly in an index with ADG and ABF, based on genetic covariances of FCE with ADG and ABF, thereby removing the need to measure FCE directly.

Animals↗

PubMed1982

Influence of Protamone on fatty liver syndrome in commercial laying hens.

Two experiments were conducted to determine the influence of Protamone on fatty liver syndrome in commercial laying hens. The addition of either 110 or 220 mg of protamone per kilogram of diet significantly lowered liver fat and also significantly reduced body weight. From histological examination of livers of hens fed Protamone it was found that the hepatocytes contained little or no lipid, whereas hepatocytes of hens fed the control diet were turgid with lipid. The addition of Protamone to the diet resulted in a significant reduction in egg production without effecting feed efficiency in Experiment 1. In Experiment 2, egg production was significantly reduced and feed efficiency improved during Days 1 to 28. However, feed efficiency was poorer during Days 29 to 56 for hens receiving the Protamone.

Animals↗

PubMed1994

Dietary arginine requirement of juvenile hybrid striped bass.

Two experiments were conducted to determine the dietary arginine requirement of juvenile hybrid striped bass (Morone saxatilis x M. chrysops); a third experiment evaluated the interaction of lysine and arginine. Diets in Experiments 1 and 2 were supplemented with graded concentrations of L-arginine-HCl, resulting in eight dietary treatments. Dietary arginine concentrations ranged from 1.0 to 2.4 g/100 g diet in Experiment 1 and from 0.6 to 2.0 g/100 g diet in Experiment 2. Weight gain was not affected by dietary treatments in Experiment 1. Feed efficiency was significantly affected by dietary arginine concentrations, and the data, when subjected to broken-line analysis, resulted in a requirement estimate of 1.53 +/- 0.20 g/100 g diet. Weight gain and feed efficiency were both significantly affected by dietary arginine concentrations in Experiment 2. Broken-line analyses of weight gain and feed efficiency data indicated the dietary arginine requirement to be 1.55 +/- 0.10 and 1.45 +/- 0.12 g/100 g diet, respectively. Diets in Experiment 3 contained lysine and arginine in ratios of 1:1, 1:1.5, 1:2 and 1:2.5 for the previously estimated requirements for both lysine:arginine and arginine:lysine. No differences were observed in weight gain or feed efficiency for fish fed various lysine:arginine ratios, but serum lysine was significantly different among treatment groups.

Amino Acids↗

PubMed1980

Long term effects of Marek's disease vaccination with cell-free herpesvirus of turkey and age at debeaking on performance and mortality of white leghorns.

Three-hundred-sixty, day-old Single Comb White Leghorn chicks were randomly placed in 8 treatment combinations. The combinations consisted of vaccinated or nonvaccinated chicks that were either not debeaked, or debeaked at day-old, 4 weeks old, or 8 weeks old. Vaccinated birds received 6,000 plaque forming units of cell-free herpesvirus of turkey vaccine per chick at day-old. Debeaking was performed by removing approximately two-thirds of the upper beak. Data were analyzed at the 5% level of probability. During the growing period (8 to 20 weeks of age), averag daily feed consumption per bird and feed efficiency for the vaccinated birds were not significantly different from those for the nonvaccinated. Regardless of the age at which debeaking was performed, the debeaked birds consumed significantly less feed and had superior feed efficiency than the nondebeaked birds. These traits were not significantly different among the various debeaked groups. Vaccination, or debeaking, or age at debeaking did not significantly influence mortality during the growing period. During the laying period (20 to 84 weeks), a significantly higher percentage of extra large eggs and a significantly lower percentage of medium eggs were collected from the vaccinated birds in comparison to those collected from the nonvaccinated. Also, average egg weight for the vaccinated birds was significantly heavier than that for the nonvaccinated. Debeaking at either 4 weeks or at 9 weeks of age caused a significant reduction in egg weight. Vaccination, or debeaking, or age at debeaking did not significantly influence hen-day egg production. Feed efficiency between the vaccinated and the nonvaccinated birds was not significantly different. Debeaking tended to improve feed efficiency. Vaccination as well as day-old debeaking significantly reduced laying house mortality. Debeaking the birds either at 4 weeks or at 8 weeks of age reduced laying house mortality numerically.

Animals↗

PubMed1994

High intensity exercise during pregnancy of rats. Effects on mother and offspring.

We see in this study the effect of high intensity exercise (90% VO2 max) in pregnant rats and their offspring depending on the length of pregnancy. The findings were compared with those obtained for sedentary pregnant rats and non-pregnant rats for similar exercise. This allowed for analysing the isolated effects of exercise (against the sedentary non-pregnant rat control group), of pregnancy and of the interaction between the two factors. For checking the effect of the length of pregnancy, each group of rats was subdivided into those with pregnancy terminated or sacrificed on the seventh, fourteenth or twentieth day of the experiment. VO2 max, post-exertion blood lactic acid level, body weight gain, food intake, feed efficiency, glucose, triglyceride, total cholesterol, total protein and albumin plasmatic concentrations in adult rats, and weight and number of offspring of pregnant rats were determined. Pregnancy increased weight gain and feed efficiency from the first week of the study, accompanied by a greater food intake (from the twelfth day). In the group of pregnant rats subjected to exercise, there was a reduction in weight gain percentage and feed efficiency in the first and third weeks, staying the same in the second week. A greater food intake during the period accompanied this recovery in the second week. In the group of non-pregnant rats subjected to exercise, food intake did not vary. As the weight gain percentage was less in relation to the non-pregnant control group, feed efficiency decreased. Pregnancy induced a drop in blood sugar level starting in the second week, and the exercise performed during pregnancy did not change this behavior. Pregnancy produced, however, an increase in plasmatic concentration of triglycerides and total cholesterol during the third week of pregnancy. Exercise performed by pregnant rats also did not change this behavior, but the increase observed in the third week was less. Exercise performed by non-pregnant rats did not change the blood sugar level and plasmatic concentration of triglycerides and total cholesterol during the entire experiment. Plasmatic concentration of total proteins and albumin showed a drop in the third week of pregnancy, probably due to high fetal use of proteins in this stage. Exercise performed by the pregnant group caused a lower protein drop in the third week, and in the non-pregnant group, determined an increase in plasmatic protein concentrations.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗