SEARCH · PubMed Health

Results for “feed efficiency”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources

PubMed2005

Magnesium proteinate is more protective than magnesium oxide in heat-stressed quail.

We evaluated the effects of dietary supplementation with Mg-oxide and Mg-proteinate on performance; nutrient digestibilities; malondialdehyde (MDA) concentrations in serum, liver, and thigh meat; and serum cholesterol and triacylglycerol concentrations in Japanese quail (Coturnix coturnix japonica) exposed to high ambient temperature. The birds (n = 360; 10 d old) were randomly assigned to 12 treatment groups consisting of 6 replicates of 5 birds each in a 2 x 2 x 3 factorial arrangement (temperature, Mg source, Mg level). Birds were maintained in temperature-controlled rooms at 22 degrees C for 24 h/d or 34 degrees C for 8 h/d (0900-1700 h) and fed a basal diet or that diet supplemented with 1 or 2 g Mg-oxide or Mg-proteinate/kg of diet. Heat exposure decreased (P = 0.0001) live weight gain, feed intake, feed efficiency, and carcass weight in quail fed the basal diet. A linear increase in feed intake (P = 0.008) and body weight (P = 0.001), and improvements in feed efficiency (P = 0.001), carcass weight (P < 0.0001), digestibility of dry matter, organic matter, crude protein, and ether extract were found in Mg-supplemented, heat-stressed quail. The effects of Mg-proteinate were greater than those of Mg-oxide (P < or = 0.0001). Serum Mg (P = 0.001) concentration increased, whereas the concentration of MDA in serum (P = 0.0001), liver (P = 0.04), and thigh meat (P = 0.0001) and serum triglyceride and cholesterol concentrations decreased linearly (P = 0.001) with the level of Mg in the diet. Interactions between dietary Mg source, temperature, and level of supplementation (P < or = 0.05) were found for several variables. Results of the present study suggest that supplementation with Mg-proteinate is more protective than Mg-oxide in reducing the negative effects of heat stress in quail.

Animal Feed↗

PubMed1980

Alternate methods of feeding alfalfa to calves.

Forty Holstein heifer calves were assigned at random among four dietary treatments: 1) an all-concentrate ration; 2) a pelleted complete ration of 20% alfalfa and 80% concentrate; 3) concentrate and alfalfa pellets fed separately, free-choice; and 4) concentrate and long-stem alfalfa hay fed separately, free-choice. Treatment diets were continued for 12 wk. Calves fed the concentrate only had reduced weight gains, feed intakes, and poorer feed efficiencies compared to treatments 2 and 4. Calves fed long-stem alfalfa hay as a roughage consumed more feed and had larger weight gains than calves fed alfalfa pellets as a roughage free-choice. The pelleted complete ration containing 20% alfalfa was comparable to a ration containing long-stem alfalfa hay free-choice for weight gains and feed efficiencies. The digestibility of dry matter and crude protein of the pelleted complete feed was similar to the digestibility of equal amounts and proportions of concentrate and alfalfa pellets fed separately. Thus, when fed free choice to early-weaned calves, pelleted alfalfa is inferior to long-stem hay for stimulating intake of dry matter. However, increasing the proportion of alfalfa pellets in a complete ration compensates for its partial loss of efficacy for elevating feed intake and growth rates.

Animals↗

PubMed1988

The acute and chronic toxicities of nivalenol in mice.

In an attempt to ascertain precisely the toxic effects of nivalenol (NIV), we conducted the determination of LD50 values, and interim kills during the carcinogenic study in mice. LD50 values (mg/kg) of NIV in 6-week-old male ddY mice were determined as 38.9 (po), 7.4 (ip), 7.2 (sc), and 7.3 (iv). Seven-week-old female C57BL/6CrSlc SPF mice were fed diets containing 0, 6, 12, and 30 ppm (mg/kg) NIV over 1 year, and were assessed for effects on body weight gain, feed efficiency, terminal organ weights, hematology, and histopathology. The rates of body weight gain and feed efficiency showed a good dose-dependent correlation in all experimental periods. Gross and histopathological evaluation of the liver, thymus, spleen, kidneys, stomach, adrenal glands, pituitary gland, ovaries, sternum, bone marrow, lymph node, brain, and small intestines with or without Peyer's patch portion from control and all NIV-exposed mice revealed that these tissues were normal in appearance and in histopathological structure. Also, no changes were observed in the ultrastructural studies on the bone marrow. Dietary NIV did, however, cause dose-dependent decreases of absolute organ weights (mg) and increases of relative organ weights (mg/g body weight) in the terminal organ weights recorded. A significant leukopenia was observed in the 30 ppm group at 6 months and in all NIV-treated groups at 1 year. No marked changes were observed in the other hematological parameters. These results indicated that 6 ppm or more of dietary NIV for 1 year showed a characteristic toxic effect of trichothecene mycotoxins in mice.

Animals↗

PubMed2005

Supplementation of zinc from organic or inorganic source improves performance and antioxidant status of heat-distressed quail.

Two sources of zinc [ZnSO4.H2O or ZnPicolinate (ZnPic)] supplementation were evaluated for their effects on performance, carcass weight, levels of malondialdehyde, and vitamins C, E, A in Japanese quail (Coturnix coturnix Japonica) exposed to high ambient temperature of 34 degrees C. The birds (n = 360; 10-d-old) were randomly assigned to 12 treatment groups consisting of 3 replicates of 10 birds each in a 2 x 2 x 3 factorial arrangement of treatments (temperatures, zinc sources, zinc levels). Birds were kept in wire cages in a temperature-controlled room at either 22 degrees C (thermoneutral) or 34 degrees C (heat stress) for 8 h/d (0900 to 1700 h) until the end of study, and fed a basal (control) diet or the basal diet supplemented with either 30 or 60 mg of Zn as ZnSO4 H2O or ZnPic/kg of diet. Heat exposure decreased (P = 0.001) live weight gain, feed intake, feed efficiency, and carcass weight when the basal diet was fed. A linear increase in feed intake (P = 0.01) and BW (P = 0.01), and improvement in feed efficiency (P = 0.01) and carcass weight (P < or = 0.05) were found in zinc-supplemented quail reared under heat-stress conditions. Serum vitamin C (P = 0.04), E (P = 0.05), and cholesterol (P = 0.01) concentrations increased linearly, whereas malondialdehyde concentrations decreased linearly (P = 0.02) as dietary zinc sulfate and ZnPic supplementation increased. An interaction between dietary zinc sources, temperature, and levels of supplementation (P < or = 0.05) for these parameters was detected. Serum vitamins C, E, and A concentrations were not different in supplemented birds reared at thermoneutral temperature. Supplementation with zinc improved carcass weight and antioxidant status of birds, and the effects of ZnPic were relatively greater than those of ZnSO4.H2O in heat-stressed quail. Results of the present study suggest that supplementation with ZnPic could be considered to be more protective than ZnSO4.H2O by reducing the negative effects of oxidative stress induced by heat stress in quail.

Animal Nutritional Physiological Phenomena↗

PubMed1975

Nonprotein nitrogen for growing chickens.

Diammonium citrate (DAC) and urea were not used beneficially as nitrogen sources in the diet of young chicks. Supplementation of 0.43% urea to a low-protein practical diet did not significantly affect gain or feed efficiency. Adding 2.85% or 5.70% DAC to a low-protein basal depressed growth and feed efficiency significantly. Percentages of nitrogen intake absorbed and retained by chicks were depressed by DAC. When diets were balanced by added amino acids. DAC did not depress weight gains, but nitrogen percentage retention was still decreased by DAC.

Animal Feed↗

PubMed1979

A comparison of methods for exposing chickens to Coccidiosis in floor-pen trials.

Three floor-pen trials were conducted for the purpose of evaluating 4 methods of exposing broiler chickens to coccidiosis. The methods were compared on the basis of their effect on weight, feed efficiency, histological lesions, and mortality. In each of the individual trials, birds exposed to coccidiosis via the feed had significantly (P is less than 0.5) higher incidence of light to severe histological lesions that those exposed via "seeder birds" or contaminated litter. On the basis of pooled data from the three trials, birds exposed via the feed had lower feed efficiency, higher mortality, and significantly (P is less than 0.5) lower weight at 8 weeks than those exposed via the other techniques. However, the feed method of exposure resulted in a significantly higher variability (P is less than 0.1) in mortality among pens. For uniformity of infection, it was concluded that the most satisfactory method of exposing birds to coccidiosis in floor pen trials was to spread laboratory sportulated oocysts over the litter.

Animal Feed↗

PubMed1999

Meal feeding is more effective than early feed restriction at reducing the prevalence of leg weakness in broiler chickens.

Two trials were conducted to investigate whether manipulation of feeding pattern or early feed intake affected the prevalence of leg weakness in broiler chickens. In Trial 1, the birds were offered two, three, or four meals per day or consumed feed ad libitum. In Trial 2, a multifactorial design was used with age at start, duration of restriction, and severity of restriction as factors. The start of restrictions were at 5, 7, or 9 d, duration of restriction was 5 or 7 d, and feed was restricted to achieve 25, 50, and 75% of predicted growth during the restriction period. Ad libitum birds served as controls. Leg weakness was assessed by gait scoring (GS) and tibial dyschondroplasia (TD) by radiography. Foot burn, hock burn, angulation of the hock joint, feed consumption, and body weight gain were also assessed. The response of the birds to meal feeding was clear. Fewer meals per day was associated with less TD, less hock burn, better walking ability, lower body weight, and better feed conversion. The response of the birds to feed restriction was also clear. Earlier restriction, longer duration, and more severe level of restriction were all associated with lower prevalence of TD, better walking ability, lower body weight, and better relative growth rates and feed efficiency. However, adjusting the observations for differences in body weight removed many of the significant differences; only birds that started feed restriction earlier had less TD. From these trials, it was concluded that meal feeding can beneficially affect the prevalence of leg weakness, and that the major part of this effect is independent of changes in body weight. It was also concluded that early feed restriction reduced many aspects of leg weakness, but that these effects were mainly a result of reduced body weight. Meal feeding and early feed restriction improved feed efficiency.

Animal Feed↗

PubMed1993

Microbially detoxified vomitoxin-contaminated corn for young pigs.

A performance trial was conducted to evaluate the effect of microbially detoxified moldy corn in a corn-soybean meal-based starter diet for young pigs. Moldy corn containing 450 ppm of vomitoxin replaced clean corn in a control diet to give a diet containing 5 ppm of vomitoxin. The same amount of moldy corn was microbially detoxified by incubation with the contents of the large intestine of chickens (CLIC) and then incorporated into the control diet to give a "detoxified" vomitoxin diet, which contained 2.1 ppm of vomitoxin. A paired diet was formulated by incorporating the untreated moldy corn into the control diet to give a diet containing the same level of vomitoxin as the "detoxified" vomitoxin diet. Clean corn was also treated with CLIC and replaced corn in the control diet to give a biologically treated control diet. Each diet was fed to six pigs (three gilts and three boars) for 5 d and then all pigs were changed to the control diet for a further 5-d feeding period. During the first 5-d feeding period, no differences were observed in pigs fed either the control diet or the biologically treated control diet. A diet containing 5 ppm of vomitoxin decreased the pigs' daily feed consumption, weight gain, and feed efficiency by 25, 57, and 45%, respectively, compared with the control diet (P < or = .05). Daily feed intake, weight gain, and feed efficiency in pigs fed the "detoxified" vomitoxin diet were 19, 54, and 37% greater, respectively, than for pigs fed the vomitoxin diet (P < or = .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed2003

Subchronic inhalation neurotoxicity studies of ethyl acetate in rats.

Rats were exposed to 0, 350, 750 or 1500 ppm of ethyl acetate by inhalation for 6 h per day, 5 days per week for 13 weeks. Functional observational battery (FOB) and motor activity tests occurred on non-exposure days during weeks 4, 8 and 13, after which tissues were microscopically examined for neuropathology. A subset of rats was monitored during a 4-week recovery period. Exposure to 750 and 1500 ppm, diminished behavioral responses to unexpected auditory stimuli during the exposure session and appeared to be an acute sedative effect. There were no signs of acute intoxication 30 min after exposure sessions ended. Rats exposed to 750 and 1500 ppm had reduced body weight, body weight gain, feed consumption, and feed efficiency, which fully or partially recovered within 4 weeks. Reductions in body weight gain and feed efficiency were observed in male rats exposed to 350 ppm. The principal behavioral effect of subchronic exposure was reduced motor activity in the 1500 ppm females, an effect that was not present after the 4-week recovery period. All other FOB and motor activity parameters were unaffected, and no pathology was observed in nervous system tissues. Operant sessions were conducted in another set of male rats preconditioned to a stable operant baseline under a multiple fixed ratio-fixed interval (FR-FI) schedule of food reinforcement. FR response rate, FR post-reinforcement pause duration, and the pattern of FI responding were not affected during or after the exposure series. In contrast, within-group FI rate for the treatment groups increased over time whereas those of the controls decreased. A historical control group, however, also showed a similar pattern of increase, indicating that these changes did not clearly represent a treatment-related effect. Results from these studies indicate a LOEL of 350 ppm for systemic toxicity based on the decreased body weight gain in male rats, and a LOEL of 1500 ppm for neurotoxicity based on the transient reduction in motor activity in female rats. In conclusion, there was no evidence that subchronic exposure up to 1500 ppm ethyl acetate produced any enduring neurotoxic effects in rats.

Acetates↗

PubMed1991

Finishing lamb performance responses to bovine and porcine somatotropins administered by Alzet pumps.

Daily injection of ovine and bovine somatotropin (oST and bST, respectively) has been shown to improve performance and carcass quality of finishing lambs. To evaluate responses to continuously released bST and porcine ST (pST), which have 99 and 91% sequence homology with oST, respectively, finishing lambs were implanted with 2-wk Alzet pumps containing bST or pST, which was released at rates of 2 or 4 mg/d. Six-week growth rate and feed efficiency responses to bST were greater than those to pST (P less than .05). Overall feed efficiency was improved 15% and growth rate was increased 16% in lambs treated with 4 mg/d of bST compared with control lambs and neither trait was affected in pST-treated lambs. Performance responses were reflected by changes in circulating glucose, blood urea nitrogen, and insulin-like growth factor I (IGF-I) concentrations. Scatchard analysis of sera with relative binding of greater than 30% revealed that average binding capacities and affinities of pST-treated lambs were 7.0 mg/liter and 6.0 x 10(9) liters/mol, respectively, and of bST-treated lambs were .8 mg/liter and 1.3 x 10(9) liters/mol, respectively. In addition, lambs with high-capacity pST antibodies had lower 6-wk IGF-I concentrations than those of controls, suggesting that these antibodies may have been attenuating responsiveness to pST. It is concluded that continuously released bST, but not pST, improves performance of finishing lambs.

Animals↗

PubMed1991

Performance and fecal flora of calves fed a Bacillus subtilis concentrate.

Eighty-four Holstein calves were assigned at 2 d of age to one of three treatments: 1) control with no additives; 2) 10 g of a mixed microbial concentrate containing Lactobacillus acidophilus, Lactobacillus lactis, and Bacillus subtilis; or 3) 10 g of a B. subtilis concentrate. The microbial concentrates were mixed with milk replacer during the a.m. feeding. The milk replacer was offered twice daily at 5% BW per feeding; the reconstituted replacer contained 12.5% DM. Volume of replacer fed was based on initial weight of calf and held constant until weaning. Water and starter ration were offered for ad libitum intake throughout the trial. Calves were weaned abruptly at 30 d of age and received only water and starter from d 31 to 44. General health and performance of all calves were good. Although differences in weight gain and feed efficiency were not significant, the B. subtilis concentrate tended to have a positive effect on feed efficiency during wk 1 to 4 and on immediate postweaning gain. A higher fecal bacilli count at 6 wk in calves fed the microbial concentrates may be related to their tendency for improved gain during d 31 to 44, the immediate postweaning period.

Animals↗

PubMed1998

Influence of tempering on the feeding value of rolled corn in finishing diets for feedlot cattle.

Crossbred yearling steers (n = 125; 372 kg) were used in a 109-d finishing trial. Steers were fed an 88% concentrate diet containing 65% corn (DM basis) as 1) dry rolled corn (DRC); 2) tempered rolled corn (TRC), 43 mg surfactant (SarTemp)/kg corn; 3) TRC, 172 mg surfactant/kg corn; 4) TRC, 430 mg surfactant/kg corn; and 5) steam-flaked corn (SFC). Corn moisture was greater (3.5%, P < .01) for TRC than for DRC but less (10%, P < .05) than for SFC. Starch enzymatic reactivity was less for TRC than for either DRC (18%, P < .05) or SFC (42%, P < .01). Tempering increased the integrity of rolled corn and reduced the amount of particles less than 2 mm in diameter by 54% (P < .01). Steam flaking corn increased (P < .01) proportion (78%) of the grain having a particle size distribution of greater than 8 mm, as compared with TRC (25%) and DRC (3%). Compared with DRC, tempering enhanced (P < .10) ADG (9%), feed efficiency (5%), and dietary NE (3%). Daily weight gain was similar (P > .10) for TRC and SFC. Feed efficiency (P < .10) and dietary NE (P < .01) were greater (6%) for SFC than for TRC. There were no differences (P > .10) between DRC and TRC in ruminal and total tract digestion of OM, N, and starch, and in ruminal microbial efficiency. Ruminal digestion of OM decreased (linear effect, P < .05) and ruminal microbial efficiency increased (linear effect, P < .05) with increasing surfactant concentration. Ruminal digestion of OM and starch, and flow of nonammonia N to the small intestine were greater (31, 56, and 14%, respectively, P < .01) for SFC than for TRC. Postruminal and total tract digestion of OM, N, and starch, and dietary DE were greater (P < .01) for SFC than for TRC. We concluded that tempering corn will enhance animal performance. Increasing the concentration of surfactant used in tempering may enhance ruminal microbial efficiency and lean tissue growth.

Adipose Tissue↗

PubMed1991

Soybean protein solubility in potassium hydroxide: an in vitro test of in vivo protein quality.

Experiments were conducted to assess protein solubility in .2% KOH as an indicator of soybean protein quality for chicks and pigs and to assess effects of particle size on protein solubility. As the particle size (micron) of soybean meal (SBM) increased, protein solubility (%) decreased (b = -.0206). In two 9-d chick trials, dehulled SBM (48% CP) was subjected to various autoclaving times and then fed as the sole source of dietary protein to young chicks. Increasing autoclaving times from 0 to 40 min at 120 degrees C resulted in a quadratic decrease in protein solubility. A broken-line model was fitted wherein gain:feed of chicks was plotted as a function of protein solubility. The analysis showed no reduction in feed efficiency with solubilities greater than 59 +/- 1.5% (mean +/- SEM). When solubility was below 59%, however, gain:feed decreased 1.5% for each 1% decrease in protein solubility. The third trial (13 d) was conducted with 7.5-kg pigs fed autoclaved SBM (44% CP) as the primary source of protein. Feed efficiency was significantly decreased when protein solubility was less than 66%. This study showed that protein solubility in KOH was a good index of in vivo soybean protein quality, and that it is important to standardize SBM particle size when applying the KOH assay.

Animal Feed↗

PubMed1981

Selection for feed conversion on efficiency and growth in mice.

Selection for feed conversion substantially influenced growth and gross feed efficiency of mice. Realized heritabilities and genic correlation for increased gain on fixed feed intake (FF) and decreased feed intake on a constant gain (FG) were estimated to be .56, .73 and -.93, respectively. The genic correlations between FF and 56-day weight and between FG and 56-day weight were estimated to be .67 and -.95, respectively. The relative efficiency in changing FF or FG by selecting directly for 56-day weight was found to be .7 in either case. When efficiency was defined as the incorporation of biomass independent of maintenance, no difference was found between selection treatments. Differences in mature weight and feed intake approached significance with selected lines having higher means than controls. The absence of a correlated response in the ability to use energy for growth indicates that selection for feed to gain ratio changes maintenance requirements but not requirements for growth.

Animal Feed↗

PubMed2000

Gonadal function, sexual behavior, feedlot performance, and carcass traits of ram lambs actively immunized against GnRH.

The effect of active immunization against GnRH on production, carcass, and behavioral traits was examined in ram lambs fed to a uniform slaughter weight. Lambs (initial BW = 32.6+/-1 kg) were stratified by BW and assigned at random to one of four treatment groups (n = 12 lambs/group). Lambs were untreated, castrated, or actively immunized against GnRH using a GnRH-keyhole limpet hemocyanin conjugate (1 mg) emulsified with either Freund's complete adjuvant (FCA) or another oil-based adjuvant (ISA). Animals were housed individually and slaughtered at 58 kg BW. Immunoneutralization of GnRH reduced (P < .05) testes weight and the concentration of testosterone in serum at slaughter. Suppression of testicular size and function was most clearly evident in animals immunized using FCA. Final anti-GnRH titer was also highest in lambs immunized using FCA. Several measures of sexual behavior (frequency of mounts and ejaculations) were also reduced (P < .05) in animals immunized using FCA. The duration of the feeding period was greater (P < .05) for castrated lambs than for untreated lambs, and intermediate feeding periods were required for FCA and ISA lambs. Average daily gain was greater (P < .05) in untreated than in castrated, FCA, or ISA lambs. Similarly, feed efficiency for untreated lambs was greater (P < .05) than for castrated, FCA, or ISA lambs, but feed efficiency did not differ among castrated, FCA, or ISA lambs. Longissimus muscle area, lean and bone maturity, overall quality, muscling score, flank streaking, and color of fat did not differ among treatments. Intact, FCA, and ISA lambs had more (P < .05) desirable yield grades, less (P < .05) backfat, and less (P < .05) marbling than castrated lambs. In summary, immunization against GnRH decreased testicular weight and reduced (P < .05) feedlot performance and sexual behavior to levels comparable to those of castrated males. Partitioning of nutrients for growth and deposition of fat, however, seems to differ among immunologically castrated and physically castrated lambs. This difference in nutrient partitioning may be due to residual testicular activity in immunized lambs.

Animal Feed↗

PubMed1990

Exogenous human growth hormone-releasing factor and ovine somatotropin improve growth performance and composition of gain in lambs.

The objectives of this study were 1) to compare intermittent subcutaneous administration of human growth hormone-releasing factor (hGRF) at two doses with a similar regimen of ovine somatotropin (oST) for effects on growth and composition of gain in growing lambs and 2) to determine whether increasing the dietary amino acid availability enhances response to oST or hGRF. Eighty crossbred ewe and wether lambs (25.5 kg live weight) were assigned randomly in pairs to receive four daily injections of excipient, 40 micrograms oST/kg BW, 5 micrograms hGRF/kg BW or 10 micrograms hGRF/kg BW for 42 (n = 80) or 56 (n = 40) d. Doses were adjusted weekly for BW. Mean plasma oST concentrations increased from 2.03 ng/ml prior to treatment to 20.64, 4.80 and 5.45 ng/ml with oST, 5 and 10 micrograms/kg hGRF doses, respectively. Lambs did not become refractory to hGRF. Cumulative gain increased approximately 18% with 7 wk of treatment with oST and the low dose of hGRF (both P less than .01), and feed efficiency improved 21% with oST and 18% with both doses of hGRF (both P less than .05). Carcass lipid accretion rate decreased 22% to 30% (P less than .001), and carcass protein accretion rate increased 30% to 36% (P less than .001) with hGRF and oST treatment, respectively. Addition of fishmeal to the diet at 4% to replace an equal amount of soy protein improved gain 8.5%; it improved efficiency 14.2% (P less than .05) across all treatments, and it significantly enhanced the effects of oST on feed efficiency (interaction P less than .12) and hind leg muscle weights.

Adipose Tissue↗

PubMed1976

The anabolic effect of estrogens on nitrogen metabolism of growing and finishing cattle and sheep.

Estrogenic compounds are effective in stimulating live weight gains and improving feed efficiency of growing and finishing ruminants. With the proper use of diethylstilbestrol or estradiol, weight gain and feed efficiency are improved approximately 15 and 12 percent, respectively. The administration of estrogenic substances to finishing cattle or sheep results in heavier carcasses containing more protein and moisture and less fat. Estrogens do not appreciably affect rumen fermentation or digestibility of the diet but improve the utilization of the absorbed nutrients. Evidence to support the concept that the increased weight gained with estrogen treatment is the result of anabolic reactions includes a decrease in plasma urea, decrease in plasma levels of most of the essential amino-acids, decreased excretion of urea and total nitrogen in the urine and increased retention of nitrogen, phosphorus and calcium. There is no change in body water space or tubular reabsorption of urea in sheep treated with diethylstilbestrol to account for some of these observations. More direct evidence that estrogens exert their major influence on nitrogen metabolism in the body and more specifically on protein synthesis comes from an experiment where cattle fed diethylstilbestrol deposited 33 percent more protein and 18 percent less fat in body weight gain as compared with control animals. The use of the hormone resulted in a significant improvement in the efficiency of utilizing dietary protein for body gain and a slight decrease in the efficiency of converting dietary energy to body gain. Enlargement of the pituitary, thyroid and adrenal glands and higher plasma levels of growth hormone, insulin and glucose have been found in experiments designed to study the effect of estrogens on the endocrine system of ruminants. These studies, along with the observation that an intact pituitary gland is necessary for estrogens to increase nitrogen retention in sheep, support the theory that estrogens are anabolic in ruminants because of increased secretion of growth hormone by the anterior pituitary. If follows that the increased secretion of growth hormone results in increased blood glucose which then stimulates secretion of insulin. Both growth hormone and insulin would be stimulatory to protein synthesis. This theory of the mode of action is further supported by the findings that injections of growth hormone closely resemble the effects of diethylstilbestrol on nitrogen retention and blood metabolites in sheep.

Anabolic Agents↗

PubMed1984

The effects of sorghum tannin and methionine level on the performance of laying hens maintained in two temperature environments.

At the conclusion of a 31-day recovery period following a previous sorghum feeding trial (Sell et al., 1983), 128 White Leghorn hens were used in a subsequent 44-day study to investigate the effects of methionine supplementation of sorghum-soybean meal diets on laying hen performance. The hens were arrayed into four nutritional treatments in each of two constant environments (22 and 28 C) based on their egg production during the last 10 days of the recovery period within a previous treatment and environment so that equal numbers of hens from the previous treatments were represented in the new treatments. Nutritional treatments consisted of either low (RS610) or high (savanna) tannin sorghum-soybean meal diets containing 13% protein and supplemented with either .2% DL-methionine (Met) or an isonitrogenous level of L-glutamic acid (Glu). With both high (HTS) and low tannin sorghum (LTS) diets, Met supplementation resulted in greater egg production, egg weight, feed intake, and less hen weight loss as compared with Glu addition, but with the exception of hen weight loss, the magnitude of the response was much greater with HTS. Hens fed the HTS diet supplemented with Glu showed greatly reduced egg production and feed efficiency as compared with those fed LTS similarly supplemented. In contrast, little difference in egg production and feed efficiency was observed between hens fed HTS and LTS diets supplemented with Met. All parameters studied except hen weight appeared to be reduced slightly by the higher temperature.

Animals↗