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PubMed2001

The effect of dietary crude protein level on intake, growth, protein retention and utilization of growing male Saanen kids.

The effects of increasing dietary levels of crude protein on growth, feed intake, feed efficiency and composition of gain in male Saanen kids were studied. Four groups of four kids each initially weighing 12.1+/-0.18kg and having a weight gain of 195+/-16g/d were penned individually and fed for 73 to 124 days up to 25kg of BW. They were fed chaffed wheat straw (45g CP/kg DM) which had been molasses sprayed (10%) and pelleted concentrates containing 8.7, 11.7, 14.4 and 17.6% crude protein (CP) on DM basis, the ratio of straw to concentrate being 1:5. Kids were fed controlled to satiation in which case small amounts of the feeds were offered about five times a day as long as the kids wanted to eat. Retention of protein, fat and energy were calculated from their initial and final concentrations in the empty body homogenates of the slaughtered kids. With increasing CP level in the diet, feed intake increased from 448 to 608g DM/d, weight gain from 94 to 181g/d, retention of protein from 9.7 to 27.8g/d, retention of fat from 9.6 to 19.1g/d and feed efficiency improved from 4.79 to 3.39kg DM/kg weight gain. Protein composition of gain increased from 103 to 154g/kg BWG while fat (103-105g/kg BWG) remained constant. Regression analyses showed that BWG can be optimized at 136g CP/kg DM and protein retention at 180g CP/kg DM, whereas, dietary nitrogen was utilized most efficiently at 120g CP/kg DM. Extrapolated from the regression equations, maintenance N requirement of the kids at zero N-retention and at zero BWG were 0.38 and 0.16g N/kg W(0.75), respectively. Recommended dietary CP concentrations and maintenance N requirements depend on the traits desired.

Journal Article↗

PubMed1988

Effect of pattern of administration on the response to exogenous pituitary-derived chicken growth hormone by broiler-strain pullets.

The effect of pulsatile versus continuous intravenous administration of exogenous, pituitary-derived chicken growth hormone (cGH) on growth performance and endocrine/metabolite status of broiler-strain pullets was determined. In a first study, 8-week-old pullets, surgically prepared with intravenous catheters and maintained via a fluid swivel/spring tether/harness system, were administered cGH or vehicle (control) over a 10-min period every 90 min (i.e., 90-min pulse pattern) for 21 consecutive days. Feed intake, body weight gain, and carcass yield and composition were determined in conjunction with plasma concentrations of several hormones and metabolites. In a second study, 8-week-old pullets were intravenously administered cGH or vehicle continuously for 21 consecutive days under the same conditions as for Study I. Pulsatile cGH administration improved feed efficiency (P less than 0.02), increased longitudinal bone growth (P less than 0.02) and mass (P less than 0.01), and reduced abdominal fat pad size (P less than 0.05) and total carcass lipid (P less than 0.09) over the 21-day treatment period in comparison to vehicle infusion. Pulsatile cGH administration also resulted in hepatomegaly, a marked elevation in plasma IGF-I (P less than 0.003) and T3 (P less than 0.005) concentrations, and a reduction in plasma T4 levels (P less than 0.04). In contrast to the above responses to pulsatile cGH, continuous intravenous cGH administration significantly impaired feed efficiency (P less than 0.01) and had no significant effect on abdominal fat pad or liver size or on total carcass lipid, but did result in widening of the epiphyseal growth plate (P less than 0.06) and increased bone mass (P less than 0.01) in comparison to vehicle infused controls. These studies demonstrate that in the broiler chicken, for which endogenous plasma GH concentrations are pulsatile at early ages in conjunction with rapid growth, the pattern of exogenous GH administration is clearly a factor influencing the nature of response to the hormone.

Animals↗

PubMed2006

Valine requirements for immune and growth responses in broilers from 3 to 6 weeks of age.

Four experiments were conducted to evaluate valine (Val) requirements in Ross 508 broilers from 3 to 6 weeks of age. Common diets were fed to broilers until 3 weeks of age. Growth and carcass measurements were taken in all experiments. Immune responsiveness measurements were taken in Experiments 1 and 2. Birds given 7.2 g Val/kg of diet in Experiment 1 had more abdominal fat than birds given 8.2 g Val/kg of diet, but there were no differences in growth or other carcass measurements. Because growth performance was not reduced in birds given 7.2 g Val/kg of diet, Val concentration was reduced to 6.4 g Val/kg of diet in Experiments 2 and 3. Increasing Val from 6.4 to 8.7 g Val/kg of diet resulted in linear increases for BW gain, feed efficiency and Val intake in male birds, and Val intake in female birds. Quadratic responses to increasing dietary Val were not observed in any experiment. There were no effects of Val on innate or adaptive immunity. A nonessential amino acid mixture containing the same nitrogen content as the L-Val additions in Experiment 4 was added and tends to support the idea that the responses to Val were specific and not due to increases in total nitrogen. Dose responses to Val resulted in male, but not female, birds given 7.3 g Val/kg of diet having improved BW gain and feed efficiency compared with birds receiving 6.4 g Val/kg of diet.

Abdominal Fat↗

PubMed1995

Dose-response effects of recombinant bovine somatotropin (Posilac) on growth performance and body composition of two-year-old rainbow trout (Oncorhynchus mykiss).

Two hundred rainbow trout (Oncorhynchus mykiss, mean weight 301.5 g) were allotted to four treatments with five replicates in a randomized block design to determine the dose-response effects of recombinant bovine somatotropin (rbST; Posilac) on growth performance and carcass composition. Treatments were sham-injected controls (S), 10 micrograms/g BW of rbST (L), 20 micrograms/g BW of rbST (M), and 30 micrograms/g BW of rbST (H). The tanks held 135 L; water flow = 15.1 L/min; temperature = 15 degrees C. The fish were maintained in a 12-h light:dark cycle and hand-fed twice daily. The fish received a single intraperitoneal (i.p.) injection on d 0 and were weighed on d 0, 14, 28, and 56. On d 56 the fish were killed. The whole body (WBW), eviscerated carcass (EC), viscera (VIS), and reproductive organ weights and the increase in average daily body length (ADL) were determined. Recombinant bST reduced (linear, P < .004) feed intake 17.6% from d 0 to 14 and improved ADG 44.8% from d 0 to 14 (linear, P < .001) and 8.1% from d 0 to 56 (linear, P < .022). Treated groups had improved (linear, P < .001) feed efficiencies for d 0 to 28. Treatment with rbST increased final weight (linear, P < .018) and length (linear, P < .001), decreased carcass dry matter (linear, P < .001) and fat (linear, P < .001), content, increased carcass ash (linear, P < .001) and tended to increase carcass protein (linear, P < .054) content. Recombinant bST increased WBW (linear, P < .018) and EC (linear, P < .003) but decreased (linear, P < .015) testes weight. Ovary weights, VIS and overall gonadosomatic index were unaffected (P > .05) by rbST. Recombinant bST was undetectable in serum samples taken on d 56 as determined by radioimmunoassay. Overall, the improved ADG, feed efficiency, body mass, and composition indicate that administration of rbST to rainbow trout may be an efficacious method of modulating growth in fish.

Animals↗

PubMed2003

Supplemental zinc and vitamin A can alleviate negative effects of heat stress in broiler chickens.

This experiment was conducted to evaluate the effects of zinc (ZnSO4.H2O) and vitamin A (retinol) supplementation on performance, carcass characteristics, and serum concentrations of glucose, cholesterol, total protein, and malondialdehyde (MDA) as an indicator of lipid peroxidation in broiler chickens (Ross) reared at a high temperature (34 degrees C). One hundred twenty 10-d-old male broilers were randomly assigned to 4 treatment groups, 3 replicates of 10 birds each. The birds were fed either a basal diet or the basal diet supplemented with either 30 mg Zn/kg diet, 4.5 mg (15,000 IU) retinol/kg diet, or 30 mg Zn + 4.5 mg retinol/kg diet. Supplemental zinc and vitamin A significantly increased live weight gain and improved feed efficiency (p<0.05). However, a combination of zinc and vitamin A, rather than each separately, provided a greater performance. Hot and chilled carcass weights and yields and the weights of internal organs with the exception of abdominal fat were greater for each supplement (p<0.05) compared to the control group. Abdominal fat decreased (p<0.05) upon dietary zinc and vitamin A supplementation. Supplemental treatments resulted in an increased total serum protein but decreased glucose, cholesterol, and MDA concentrations. The results of the study show that, separately or as a combination, zinc and vitamin A supplementation resulted in an improved live weight gain, feed efficiency, and carcass traits, as well as a decrease in serum MDA concentrations. The results of the present study also suggest that zinc and vitamin A have similar effects and that a combination of zinc and vitamin A may offer a potential protective management practice in preventing heat-stress-related depression in performance of broiler chickens.

Animals↗

PubMed1984

Phenylalanine and tyrosine requirements of immature beagle dogs.

Experiments were conducted with immature Beagle dogs to determine the dietary requirement for phenylalanine. With purified L-amino acid diets the requirement for this aromatic amino acid to optimize growth, feed efficiency and nitrogen balance was found to be 0.8%. Dietary limitations in the quantity of phenylalanine resulted in an increase in plasma and urinary urea. Breakpoint analysis of plasma phenylalanine concentrations also indicated a dietary requirement of 0.8%. The present data indicate that the dietary requirement for phenylalanine can be met by supplying approximately 195 mg per 100 kcal metabolizable energy or 518 mg per kilogram body weight per day. In a separate study, tyrosine was found to meet approximately 46% of the phenylalanine requirement of the immature dog. Consumption of diets containing tyrosine in the presence of optimal phenylalanine did not further stimulate growth, feed efficiency or nitrogen balance.

Administration, Oral↗

PubMed1991

Effects of varying dietary undegradable protein on dry matter intake, growth, and carcass composition of Holstein calves.

The objective was to study the effect of feeding diets varying in rumen undegradable protein on DMI, growth, feed efficiency, and carcass composition in Holstein calves from birth to 25 wk of age. Sixty Holstein calves were assigned in a randomized complete block design to one of three dietary treatment groups that differed in rumen undegradable protein as a percentage of total protein. Protein undegradabilities of the TMR fed for ad libitum intake for period 1 (wk 1 to 12 of age) were 33, 37, and 46% and for period 2 (wk 14 to 25 of age) were 30, 34, and 38%. Intake was not different among diets during period 1. During period 2, animals fed the highest and lowest levels of undegradable protein diet consumed less DM, and those animals on the highest undegradable diet had the least amount of crude protein intake. Feed efficiency was increased with increasing rumen undegradable protein for period 2. Carcass composition was not affected by dietary treatment for either 9-10-11 rib section or the half carcass. Prediction equations for carcass protein and fat were calculated for 25-wk Holstein calves using urea space and live weight. These results indicate that the amount of undegradable intake protein currently recommended for growing dairy replacements may not be justified when intake is ad libitum. In the present study, urea space was not found to be beneficial over live weight for predicting carcass protein and fat in intact male or female Holstein calves.

Animal Feed↗

PubMed1999

Direct and correlated responses to selection for efficiency of lean gain in mice.

Improvement in feed efficiency when selection is based on gain:feed ratio has often been accompanied by a reduction in feed intake. The following four criteria were used in mass selection for improved lean gain efficiency in mice with an objective of evaluating changes in lean gain and intake: 1) gain deviation, animals selected had the greatest gain in fat-free mass (FFM) after adjustment to a constant intake; 2) intake deviation, mice selected had the least feed intake after adjustment to a constant gain in FFM; 3) intrinsic efficiency, similar to the second criterion except that adjustment was also made for average weight maintained during the period; and 4) a positive control that used the ratio of gain in FFM: feed intake as the selection criterion. A fifth line, in which a male and a female were selected at random from each litter, served as a negative control. Experimental animals were outbred mice of the CF1 strain. Two replicates of the five lines were included in the study. Twelve males and females were pair-mated within each line-replicate combination each generation. Feed disappearance was measured from 25 to 42 d. Mice were scanned to obtain an electrical conductivity measurement for prediction of FFM. After six generations of selection, realized heritabilities for gain:feed, gain deviation, intake deviation, and intrinsic efficiency were .00 +/- .04, .04 +/- .29, .35 +/- .08, and .28 +/- .06, respectively. There were no differences among lines for gain:feed ratio. The correlated response in feed intake reduction was significant in the intake deviation and intrinsic efficiency lines (-.17 +/- .05 and -.21 +/- .04 g x d(-1) x generation(-1), respectively). The realized genetic correlations between the ratio and gain deviation, intake deviation, and intrinsic efficiency were .83 +/- .15, .01 +/- .04, and .21 +/- .12, respectively. Litter size was depressed in all selected lines.

Animals↗

PubMed2002

Long-term effects of diet on leptin, energy intake, and activity in a model of diet-induced obesity.

This study investigated the effect of long-term high-fat sucrose (HFS) or low-fat complex-carbohydrate (LFCC) diet consumption on leptin, insulin, fat cell size, energy intake, and markers of activity to ascertain the role that leptin plays in long-term energy balance in a model of diet-induced obesity. Female Fischer 344 rats were fed either a HFS or LFCC diet ad libitum for a period of 20 mo. Measurements of leptin concentration, insulin concentration, and adipocyte size were performed at 2 wk, 2 mo, 6 mo, and 20 mo. Body weight and energy intake were measured weekly for calculation of feed efficiency. Body temperature and activity levels were assessed over a 5-day period after 12 mo of the dietary intervention. Plasma leptin and insulin concentrations were significantly elevated within 2 wk of HFS diet consumption and remained elevated throughout the course of the study. After 2 mo, the adipocytes of the HFS group were significantly larger and continued to increase in size throughout the course of the study. A significant correlation was noted between leptin and adipocyte cell size (r = 0.96, P < 0.01). However, despite elevated leptin, energy intake was similar, and the HFS group weighed significantly more than the LFCC group, as a result of a higher feed efficiency. There were no significant differences in body temperature or activity levels between the groups. These results demonstrate that a HFS diet causes hyperleptinemia and hyperinsulinemia before adipocyte size is increased and suggests that leptin resistance may be present or, alternatively, that leptin does not to play a major role in the long-term regulation of energy intake or activity levels in this model.

Adipocytes↗

PubMed2001

Lysine and arginine requirements of broiler chickens at two- to three-week intervals to eight weeks of age.

Four experiments were conducted to determine the arginine and lysine requirements of male chickens for 2- to 3-wk intervals from the time of hatching until 8 wk of age. Weight gain, breast muscle growth, and feed efficiency were used as response for each interval. Dietary requirements for lysine and arginine were estimated by broken-line regression analysis of responses to six or seven dietary levels of each amino acid. Dietary crude protein levels were 22, 21, 20, and 18% in four consecutive experiments from 0 to 2, 2 to 4, 3 to 6, and 5 to 8 wk of age. An occasional estimate of requirement was not determined (ND) because the response did not conform to the regression model. The values for lysine and arginine requirements determined from breast muscle gain (weight gain of pectoralis major plus pectoralis minor) were not significantly higher than those from body weight gain. However, they tended to be higher than for feed efficiency for 0-to-2 and 2-to-4-wk-old broilers. Lysine and arginine requirements, as percentages of total amino acid in the diet, for maximum breast muscle growth were, respectively, 1.32+/-0.01% and 1.27+/-0.00% to 2 wk of age, 1.21+/-0.06% and ND for 2 to 4 wk of age, 0.99+/-0.02% and 0.97+/-0.02% for 3 to 6 wk of age, and 0.81+/-0.01% and 0.83+/-0.02% for 5 to 8 wk of age. Calculated digestible lysine and arginine requirements were, respectively, 1.24 and 1.19% to 2 wk of age, 1.11% and ND for 2 to 4 wk of age, 0.92% and 0.91% for 3 to 6 wk of age, and 0.75 and 0.78% for 5 to 8 wk of age. The requirements for lysine and arginine were similar except for the earliest age group for which the lysine requirement appeared to be slightly higher than that of arginine.

Age Factors↗

PubMed1998

Methionine and somatotropin supplementation in growing beef cattle.

This objective of this study was to determine the effects of supplemental bovine somatotropin and supplemental ruminally protected methionine (Met) on ADG, feed efficiency (FE), body composition (BC), and serum concentrations of Met, ST, IGF-I, and progesterone in growing beef cattle. Two experiments were conducted. In one experiment, 24 growing beef cattle (6 steers and 18 heifers, 410 +/- 2 kg) were divided into two treatment groups, either controls or Met-treated animals. In a second experiment, 32 heifers and 8 steers (311 +/- 2 kg) were used in a completely randomized design experiment (four treatments; two pens/treatment). Treatments were arranged as a 2 x 2 factorial, with main effects of ST (0 or 33 microg/kg BW per day) and Met (0 or 6 g x animal(-1) x d(-1)). Feed efficiency and ADG were not affected by Met. However, ST increased FE and ADG (P < .05). Serum Met concentrations tended (P = .08) to increase with Met administration and remained unchanged by ST administration. Serum ST and IGF-I concentrations were increased (P < .05) by ST administration but unchanged by Met administration. The BC and heifer serum progesterone concentrations were similar across treatments, and no interactions (P > .10) were observed between ST and Met. In summary, ST improved BW gain and FE. Methionine was not the first-limiting AA in the diet fed.

Animals↗

PubMed1983

Performance and carcass quality of swine injected daily with bacterially-synthesized human growth hormone.

In this study, growth rate, feed intake, feed efficiency and carcass quality were measured in pigs (24 barrows and 24 gilts, initial body weight = 23.0 +/- 4 kg) administered 0, .015, .030 or .060 mg/kg/day bacterially produced human growth hormone (hGH) until slaughter weight of 90 kg. Administration of hGH on the first treatment day resulted in a dose-dependent peak in serum concentration after 2 hrs and concentrations gradually returned to baseline by 22 hrs after treatment. Measurement of glucose, insulin and glucagon on the first and last days of treatment showed variable effects of treatment. In pigs treated with .015 mg/kg/day hGH average daily weight gain (.89 vs .82 kg, p less than .05) and feed intake (4.59 vs 4.25 kg, p less than .006) were increased, while feed efficiencies were not different among groups. The carcass data did not show consistent differences to indicate a hGH growth response. It is concluded that hGH may be effective in pigs for improving growth rate and at doses lower than those shown effective for porcine GH.

Animals↗

PubMed1983

Influence of dietary zinc or cadmium on hair and tissue mineral concentrations in rats and goats.

Three experiments were conducted to determine whether concentrations of minerals in hair and other tissues of rats and goats are affected by level of dietary Zn or Cd. In the first experiment, rats were fed diets that contained 10.3, 20.5, 33.7, 41.3 or 52.9 micrograms Zn/g for 57 d. Rats fed the diet that contained 10.3 micrograms Zn/g suffered from mild Zn deficiency, as indicated by depressed feed intakes and slower growth rates than rats fed diets containing higher amounts of Zn. Zinc concentrations in hair (P less than .01), liver (P less than .01) and kidney (P less than .01) increased as dietary Zn increased. Confidence intervals for dietary Zn concentration predicted from Zn analysis of hair were large. In the second experiment, rats were fed diets that contained .1, 4.0, 7.6, 10.1 or 15.9 micrograms Cd/g for 57 d. Total growth, feed intake, feed efficiency and liver, kidney and testes weights were not affected (P greater than .05) by dietary Cd concentration. Cadmium increased linearly in liver (P less than .01) and kidney (P less than .01) and quadratically in testes (P less than .01) as Cd intake increased, but Cd in hair was not affected by dietary level of Cd. High correlations between Cd concentrations in liver (R2 = .88) and kidney (R2 = .90) and dietary Cd concentration indicate that Cd intakes of rats may be accurately predicted from Cd analyses of these tissues. In the third experiment, goats were fed diets containing 0, 10.4, 18.0 or 28.5 micrograms Cd/g for 125 d. Growth, feed intake, feed efficiency and liver and kidney weights were not affected by dietary Cd intake. Cadmium in hair samples was not affected by level of dietary Cd; however, cadmium in liver (P less than .01), kidney (P less than .01) and proximal duodenum (P less than .01) increased as dietary Cd increased. Cadmium in liver, kidney, lungs and proximal duodenum was highly correlated (R2 = .67, .89, .57, .49, respectively) with dietary Cd concentration.

Animals↗

PubMed1991

Effect of active immunization against growth hormone-releasing factor on growth and onset of puberty in beef heifers.

Angus and Charolais heifers (195 +/- 7 kg) were actively immunized against growth hormone-releasing factor (GRF) to evaluate the effect on concentrations of somatotropin (ST), insulin-like growth factor I (IGF-I), insulin (INS), growth, and onset of puberty. Primary immunizations were given at 184 +/- 7 d of age (d 0 of experiment) by injecting (s.c.) 1.5 mg of GRF-(1-29)-Gly-Gly-Cys-NH2 conjugated to 1.5 mg of human serum albumin (GRFi, n = 22) or 1.5 mg of human serum albumin (HSAi, n = 21). Booster immunizations of .5 mg of antigen were given on d 62, 92, 153, and 251. Antibody binding (percentage at 1:2,000 dilution) to [125I]GRF on d 69 was greater (P less than .01) in GRFi (53.7 +/- 4.5) than in HSAi (10.1 +/- .6) heifers. Serum concentration (ng/ml) and frequency (peaks/5 h) of ST release, respectively, on d 78 were lower (P less than .01) in GRFi than in HSAi heifers (3.3 +/- .1 vs 5.6 +/- .2 and .9 +/- .3 vs 2.3 +/- .2). Serum IGF-I (ng/ml) was lower (P less than .01) in GRFi than in HSAi heifers on d 69 (41 +/- 5 vs 112 +/- 4). Serum INS (microU/ml) on d 78 was lower (P less than .05) in GRFi (2.2 +/- .1) than in HSAi (3.8 +/- .2) heifers. Feed intake, ADG, and feed efficiency were lower (P less than .05) in GRFi than in HSAi heifers. Hip height was lower (P less than .01) and fat thickness was greater (P less than .05) in GRFi than in HSAi heifers by d 132 and 167, respectively. Percentage of heifers attaining puberty (progesterone greater than 1 ng/ml for two consecutive weeks) by d 209 and 379 (12.9 and 18.5 mo of age), respectively, was lower (P less than .05) in GRFi (40.9 and 45.5) than in HSAi (81.0 and 100). In conclusion, growing heifers were successively immunized against GRF. Active immunization against GRF resulted in decreased serum concentration of ST, IGF-I, and INS. In addition, GRF immunization led to lowered feed intake, ADG, and feed efficiency, increased fat depth, and delayed onset of puberty in heifers. We propose that ST and IGF-I are important metabolic mediators involved in the initiation of puberty in heifers.

Animals↗

PubMed1985

Effect of dietary crude protein level on the reproductive performance and growth of New Zealand white rabbits.

An experiment utilizing 391 preweaning and 187 postweaning litter records from 145 does was conducted for 12 mo to determine the effect of dietary crude protein level on performance of commercial New Zealand White rabbits. Does and their litters were fed alfalfa-based pelleted diets containing either 17.5, 19 or 20.5% crude protein (CP). In a separate experiment, the 17.5 and 20.5% CP diets were fed during lactation to 10 does to determine nitrogen (N) digestibility and retention. Body weights of does fed 17.5% CP were lower (P less than .01) than for the other treatments after 21 and 28 d of lactation. No differences (P greater than .10) were observed for doe weight at kindling, percentage fertility, litter size, preweaning litter mortality, 1- to 21-d consumption, preweaning feed efficiency and 28- to 56-d average daily consumption, average daily gain and average weight. Total born tended to be higher (P = .07) on higher protein levels but percentage born alive was greatest (P less than .01) on the 17.5% CP diet. Does fed 19% CP tended to have a greater number of parities (P = .06). Other significant differences observed for preweaning litter traits were between 17.5 and 19% CP groups. Does fed 19% CP had heavier litters at birth (P less than .01), at 21 d (P = .05) and 28 d (P = .06) and had greater 1- to 21-d litter gains and 21- to 28-d consumption (P = .05) than those fed 17.5% CP. For postweaning performance, feed efficiency values were lowest and mortality was highest for litters fed 20.5% CP. When litters were switched to different diets after weaning, mortality tended to be higher (P = .07) for animals that were fed 20.5% CP before weaning. The month of experiment effect did not influence any of the characters studied (P greater than .05). Parity number was important for percentage fertility, percentage born alive, litter birth weight and doe weight at 21 and 28 d (P less than .05). Does at first parity showed the poorest performance for all traits (except percentage fertility). Fertility fluctuated throughout the first four parities and then steadily declined. Does fed 20.5% CP had greater apparent dry matter and acid detergent fiber digestibilities and N intakes (P less than .05) and retained 90% more N during lactation (P = .22) than does fed 17.5% CP. Milk production and CP digestibility did not differ between the two diets tested.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1976

Lysine needs of rapidly growing turkeys from 12-22 weeks of age.

Two experiments were conducted with Large White male turkeys to investigate the lysine requirement from 12 to 22 weeks of age. Six pens of 20 turkeys were fed each of the experimental diets. In experiment 1, a basal diet containing wheat, meat meal, cottonseed meal and distillers dried grains with solubles was supplemented with four levels of L-lysine. Lysine at 4.27% of protein and 2.31 g./mcal. of metabolizable energy from 16 to 20 weeks of age, and 1.83 g. from 20 to 22 weeks of age was inadequate for optimum growth and feed efficiency (16-22 weeks). Supplementing the diet with lysine from soybean meal gave performance equivalent to synthetic lysine, indicating that it was fully available. Performance of turkeys fed a diet containing 88% triticale from 16 to 20 weeks of age, and 72% from 20 to 22 weeks of age was equivalent to that of turkeys fed a more complex ration with an equivalent level of lysine. In experiment 2, Large White male turkeys were fed a basal diet composed largely of triticale and soybean meal from 12 to 20 weeks of age with different levels of added lysine. From 12 to 16 weeks of age, 3.11 g. lysine/mcal. of M.E. (4.9% of protein) was adequate for optimum growth and feed efficiency. From 16-20 weeks of age 2.36 g. lysine/mcal. of M.E. (4.3% of protein) was adequate for optimum performance. Although the estimated requirement from 16 to 20 weeks of age based on the two experiments differs (perhaps because of differences in lysine availability), the results suggest that the current N.R.C. recommendation may be higher than necessary.

Age Factors↗

PubMed1980

Sexual maturation of boars and growth of swine exposed to extended photoperiod during decreasing natural photoperiod.

Littermate pairs of crossbred boars, barrows and gilts were used to study the effects of an artificially extended photoperiod during decreasing daylength on puberty in boars and on weight gain and feed efficiency. Libido scores of the boars exposed to the extended photoperiod were higher (P < .01) than those of controls at 24 and 26 weeks of age. At 26 weeks of age, semen had been collected from 74% of the boars on supplemental light but from only 26% of the controls. Lighting treatment did not affect semen quality. The number of ejaculates previously collected did affect semen quality. Motility and total sperm per ejaculate increased with increasing ejaculate number, while the percentage of abnormalities appeared to decrease. A second group of boars was delayed in the development of mating behavior, perhaps because of inadvertent consumption of Gibberella zeae-infected corn. The extended photoperiod did not exert a beneficial effect on weight gain or feed efficiency of boars, barrows or gilts.

Animals↗

PubMed1997

Olestra's effect on the status of vitamins A, D and E in the pig can be offset by increasing dietary levels of these vitamins.

Groups of weanling pigs (5 castrated males, 5 females per group) were fed purified diets containing the NRC's requirements for nutrients and 0, 1.1, 4.4 or 7.7% olestra for 12 wk. Graded concentrations of vitamins A, D2 and E were added at each olestra concentration. The primary purpose of the study was to establish relationships between dietary concentration of olestra and the amounts of vitamins A, D2 and E needed to restore tissue concentrations of these vitamins to control concentrations. A secondary purpose was to confirm that olestra does not affect the status of vitamin K or water-soluble nutrients. Liver concentrations of vitamins A, E and B12, iron and zinc and bone concentrations of ash, zinc, calcium and phosphorus, were measured in a group of pigs killed at the start of the study and in all pigs killed at wk 12. Growth, feed efficiency, hematology, clinical chemistry, blood concentrations of retinol, alpha-tocopherol, 25-hydroxyergocalciferol, 25-hydroxycholecalciferol, 1,25-dihydroxyvitamin D, folate, iron, total iron-binding capacity, zinc and calcium and adipose concentration of vitamin E were measured at 4-wk intervals. Prothrombin time was measured weekly for the control and 7.7% olestra groups, monthly for others. Relationships derived from measured tissue concentrations of vitamins A and E showed that constant amounts of the vitamins were required per unit mass of olestra in the diet to restore tissue concentrations to control values. Such a relationship could not be determined for vitamin D because exposure of the pigs to UV light resulted in an apparent interaction between vitamin D2 and vitamin D3. Olestra did not affect growth, digestible feed efficiency, vitamin K status or the status of the water-soluble micronutrients, in agreement with other studies in the pig.

Animals↗