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At least 325 records · Page 18Linked to original sources

PubMed1984

A study of heterosis and recombination loss in crosses of inbred Leghorn lines derived from a common base population.

This study was designed to estimate heterosis and recombination loss of feed efficiency at peak egg production using six inbred White Leghorn lines and their crosses. Percent hen day egg production was highest in three-line crosses with 94.6%, 93.5% for two-line crosses and 91.0% for inbred lines, respectively. Feed efficiency of three-line crosses was superior to that of two-line crosses, primarily because of low feed consumption. Heterosis effects for body and egg weights were observed in all mating combinations. The value of heterosis for egg number and feed efficiency were dependent upon parental line. Egg number and egg weight showed small average recombination losses, depending on lines involved. Small but consistent recombination loss for body weight was observed. The recombination loss for feed efficiency was large and negative; the highest three-line cross value for this trait was about 16% above that of the mean of the corresponding two-line crosses.

Animals↗

PubMed1980

The effect of vitamin B12 on the tolerance of chicks for high levels of dietary fat and carbohydrate.

Three experiments were conducted with White Leghorn chicks hatched from hens fed diets varying in levels of protein, fat, and vitamin B12. Adding animal fat at a level of 10% in the chick diet caused growth depression of vitamin B12 deficient chicks, regardless of protein or energy level of hen or chick diet. Increasing the level of fat to 20% in the chick diet caused further growth depression and increased mortality. Feed efficiency of vitamin B12 deficient chicks was severely depressed by each additional increment in the fat level. Increasing protein content from 20 to 30% in the chick diet resulted in severe growth depression and poor feed efficiency. Although the added fat in the 30% protein chick diet depressed growth of chicks hatched from hens fed the 16 and 32% protein with added fat, it improved growth of those hatched from hens fed the similar diets with no added fat. Added fat in the 30% protein chick diet also improved feed efficiency of all chicks regardless of breeder diet treatments. Chicks hatched with an adequate carry-over of vitamin B12 from hens or chicks fed a diet with 10 micrograms of added vitamin B12/kg of feed did not show the growth depression caused by the high level of fat in the 20 and 30% protein chick diets. Feed efficiency was greatly improved by the addition of vitamin B12 to all chick diets. In a 22% protein vitamin B12 deficient diet, isocaloric substitution of glucose for fat depressed chick growth significantly and this growth depression was counteracted by supplementing the diet with 10 or 100 micrograms of vitamin B12/kg of feed. The vitamin B12 requirement was not increased by such substitution in the 22% protein diet. In contrast, isocaloric substitution of fat for glucose in the 32% protein chick diet increased the vitamin B12 need for optimum growth.

Animals↗

PubMed1985

Sexual dimorphism in early feed and water intake of broilers.

Four trials were conducted utilizing two nonselected (randombred) and two selected (commercial broiler) stocks to investigate sex divergence in feed and water intake, and feed efficiency immediately posthatch. Although differences between sexes in body weight were not significant until 4 days of age, male:female ratios indicated that divergence in body weight started immediately posthatch and increased in a more or less linear fashion with age. At 14 days of age males were 7% larger than females (ratio 1.07) in both selected and nonselected stocks. The male:female ratios for feed intake followed the same general pattern as body weight ratios, starting at low levels immediately posthatch and increasing to the same approximate levels (ratio 1.07). Conversely, the male:female water intake ratios indicated that males consumed more water (4 to 9%) than females immediately following hatch and maintained constant rather than increasing ratios through 12 days. Feed efficiency and water:feed ratios were higher for males than females with the magnitude of the difference greater immediately posthatch. Data from these experiments indicated that both feed intake and feed efficiency are involved in the early body weight divergence between males and females.

Age Factors↗

PubMed1983

Studies on the utilization of leaf protein concentrates as a protein source in poultry nutrition.

Spray-dried leaf protein concentrate prepared from Red Clover and alfalfa with low or high saponin content were evaluated by studying their effect on growth and feed efficiency of broiler chicks at the 40% level. Excellent growth and feed efficiency were recorded when 40% of low saponin alfalfa protein concentrate (APC) prepared from fresh alfalfa was incorporated in the diets. Saponin in APC estimated by hemolysis test was an important factor affecting the growth, feed efficiency, and mortality of chicks. Analysis of variance showed no significant (P less than .05) difference in body weight gain between Red Clover protein concentrate and low saponin APC. A significant reduction in body weight gain of both broiler and egg type chicks was observed when 40 parts of wet alfalfa protein concentrate were incorporated in the diets. A combination of 30 parts of wet alfalfa protein concentrate (wet APC) and rice bran in a broiler diet did not adversely affect growth. Supplementation of additional vitamins did not improve gain in body weight when 40 parts of wet APC and rice bran were included in the diet. Supplementation of vitamin E seems to be crucial when higher levels of wet APC and rice bran are included in broiler diets.

Animals↗

PubMed1995

Effects of supplemental ascorbic acid on the performance of broiler chickens exposed to multiple concurrent stressors.

An experiment was conducted to determine whether ascorbic acid (AA) increases resistance of female Hubbard x Hubbard broiler chicks to multiple concurrent stressors. Stressors imposed from 10 to 17 d posthatch included 2 x 2 x 2 factorial combinations of beak trimming [(B), sham-operated or beak-trimmed and cauterized], coccidiosis [(C), gavage with 0 or 3 x 10(5) sporulated Eimeria tenella oocysts], and heat stress [(H), 28 vs 33 C]. A starter diet was supplemented with AA to provide 0, 150, or 300 ppm (milligrams per kilogram). This resulted in a 2 x 2 x 2 x 3 factorial design with two six-chick replicates of each of the 24 treatment combinations. Data were analyzed using ANOVA and a level of 95% significance. Ascorbic acid increased feed intake and lowered plasma corticosterone and heterophil:lymphocyte ratios. Heat depressed weight gain and feed intake and elevated heterophil:lymphocyte ratios. Heat and AA interacted to improve weight gain and feed intake and lower heterophil:lymphocyte ratios. Coccidiosis depressed weight gain, feed efficiency, and heterophil:lymphocyte ratios. Coccidiosis and AA interacted to increase feed intake and lower plasma corticosterone and heterophil: lymphocyte ratios. Beak trimming increase heterophil:lymphocyte ratios. Beak trimming and AA interacted to increase feed intake and lower heterophil: lymphocyte ratios. Weight gain and feed efficiency decreased whereas heterophil:lymphocyte ratios increased linearly in unsupplemented birds as a function of stressor "order" (the number of stressors imposed simultaneously) indicating an additive effect of systematically increasing the number of stressors. No changes in feed efficiency or heterophil:lymphocyte ratios were detected as a function of stressor order when AA was provided. Ascorbic acid reduced the slope of the regression equation describing the relationship between weight gain and stressor order. It was concluded that AA, particularly at 150 ppm, enhanced performance of broiler chicks exposed to multiple concurrent environmental stressors.

Animals↗

PubMed1990

Feed restriction of turkey breeder hens--a review.

Past research on feed restriction methods with turkey breeder hens has involved the feeding of 1) high-fiber or low-energy diets, 2) low dietary protein, 3) limited quantities of feed, 4) rations on a skip-a-day program, 5) distasteful compounds, or 6) combinations of these methods. In general, feed-restricted turkey breeder hens showed a reduction in BW and a delay in sexual maturity at time of lay with no effect on fertility, hatchability of fertile eggs, and hatchability of all eggs set. Egg weight was unaffected in 13 studies, but decreases and increases were reported for two and three studies, respectively. The results on egg production and feed efficiency (number of eggs/unit of feed) were more variable. Egg production decreased, increased, or had no effect in 6, 2, and 14 of the feed restriction programs, respectively. Feed efficiency of restricted hens either was poorer (two reports), improved (three studies), or had no effect (six studies). The larger parent-stock breeder candidate of today may not respond to these feed restriction programs in the same manner as the breeder hens of the 1970s and early 1980s. Most likely, more severe feed restriction programs will have to be designed to lower the BW of these larger hens.

Animals↗

PubMed1993

Effects of sex, heat stress, body weight, and genetic strain on the dietary lysine requirement of broiler chicks.

Experiments were carried out to investigate the effects of sex, heat stress (37 C), body weight (heavy and light within strain), and strain of chicks on the dietary lysine requirement of chicks during 8 to 22 days posthatching. A lysine-deficient basal diet (.64% total lysine, 23% CP, 3,200 kcal ME(n)/kg) containing corn, feather meal, and soybean meal was supplemented with graded levels of L-lysine.HCl to produce growth response curves. The lysine-deficient diet contained .52% true digestible lysine as determined with a precision-fed cecectomized adult cockerel assay (Experiment 1). Hubbard x Hubbard chicks were used in Experiment 2 and New Hampshire x Columbian crossbred chicks were used in Experiments 3 and 4. Experiment 2 compared lysine requirements of male and female chicks. Weight gains between sexes were similar when diets were deficient in lysine, but males grew faster than females when lysine-adequate diets were fed. Male chicks required a higher level of dietary lysine than females for both maximal weight gain and feed efficiency. Also, regardless of sex, the lysine requirement (percentage of diet) for maximal feed efficiency was higher than that for maximal weight gain. In Experiment 3, heat stress reduced weight gain and feed intake of both males and females by about 22%, and it increased the lysine requirement of female but not male chicks. In Experiment 4, light and heavy chicks were selected from male and female populations. Heavy and light chicks exhibited the same dietary lysine requirement for maximal growth. However, the lysine requirement for maximal feed efficiency was higher for heavy birds than for light birds.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed1988

Effect of anabolic steroids, alone or in combination with antibiotics, on bull performance, carcass traits and meat quality characteristics.

Two trials were conducted with 32 and 39 finishing Belgian white-red bulls, treated with anabolic agents during 55 to 60 days prior to slaughter. Xenobiotic androgens and estrogens, together with (Exp. I) or without progesterone (Exp. II) were injected at three-week intervals. Diets consisted of maize silage and 7.5 g concentrate daily per kg liveweight. Half of the animals within each experiment received an antibiotic for the entire fattening period lasting about 285 days. Lasalocid-sodium (Exp. I) and virginiamycin (Exp. II) were incorporated at 65 mg per kg concentrate. Anabolic agents improved average daily gain from 1.06 to 1.20 kg (P less than 0.10) and from 1.24 to 1.42 kg (P less than 0.05) respectively. In both trials steroidal growth promoters stimulated intake and improved feed efficiency (P less than 0.10). Feed antibiotics did not significantly affect daily gain during this short term finishing period. A reduced feed intake (P less than 0.05) and improved feed conversion were observed for lasalocid, while there was no difference for virginiamycin. Dry matter intake amounted to 80.5 and 76.3 g per kg metabolic weight and 9.02 and 8.41 kg per kg gain, respectively for control and lasalocid treated animals. The data were 79.6 and 80.3 g and 7.30 and 7.34 kg, respectively, for the experiment with virginiamycin. No significant interaction between anabolics and antibiotics was obtained with respect to gain and feed efficiency. Dressing percentage, carcass composition, carcass grading and meat traits were not affected by anabolic treatment or antibiotic supplementation.

Anabolic Agents↗

PubMed2001

Intake restriction strategies and sources of energy and protein during the growing period affect nutrient disappearance, feedlot performance, and carcass characteristics of crossbred heifers.

Two trials were conducted to evaluate intake restriction, energy, and protein source on the performance and carcass merit of heifers limit-fed corn gluten feed. Trial 1 crossbred heifers (n = 140) were allotted to ad libitum wet corn gluten feed (WCGF)-hay, ad libitum WCGF-corn, WCGF-corn continuously limit-fed to achieve a gain of 1.1 kg/d or WCGF-corn fed in the following sequence: 70% of ad libitum for 20 d, ad libitum for 20 d, and 2 d common intake during the 84-d growing period. One-half of these restricted-refed heifers received a rumen-undegraded protein supplement, and the other half received a rumen degraded protein supplement. Heifers were fed a common finishing diet ad libitum subsequent to the growing period. Heifers offered ad libitum WCGF-hay and WCGF-corn were slaughtered at a common compositional fat end point. Heifers limit-fed WCGF-corn were slaughtered at the same time as heifers offered ad libitum WCGF-corn, regardless of subcutaneous fat cover. Limit-feeding WCGF-corn diets to growing heifers reduced ADG (P < or = 0.01) but did not compromise feed efficiency. Method of intake restriction, continuous or ad libitum-interrupted, and supplemental protein source did not affect combined growing-finishing performance. However, when fed for a common length of time, the average of the limit-fed heifers had lighter carcass weights (P < or = 0.01) and lower (P = 0.04) marbling scores. Heifers offered ad libitum WCGF-hay gained slower (P < or = 0.01) and less efficiently (P < or = 0.01) than heifers offered WCGF-corn. Trial 2 crossbred heifers (n = 222) were allotted to dry corn gluten feed (DCGF)-corn ad libitum or restricted to 80% of ad libitum for 42, 84, or 126 d; or ad libitum corn silage or DCGF-corn silage at 80% of ad libitum for 84 d. Feed efficiency (P = 0.07) and ADG (P = 0.08) tended to behave quadratically, being poorer for heifers limit-fed for 126 d during the growing period. Heifers limit-fed DCGF-corn gained more efficiently (P = 0.05) than heifers grown on ad libitum corn silage. Limit-feeding CGF-corn to growing beef heifers can be used to achieve moderate rates of gain without compromising feed efficiency. However, limit-feeding during the growing period may result in lighter weight carcasses with lower quality grades if not fed to the same fat end point as heifers grown with free access to concentrate.

Animal Feed↗

PubMed1990

Broiler chick response to low protein diets supplemented with synthetic amino acids.

Performance of broiler chicks fed low protein diets supplemented with several essential amino acids (EAA) is generally inferior to that of birds fed a higher protein diet composed primarily of intact protein. Two experiments were conducted to determine whether lowering the minimum requirements of the EAA in proportion to the lowered protein concentration or equalizing the dietary amino nitrogen content by use of glutamic acid would prevent the reduction in performance. Chicks were fed the experimental diets from 7 to 21 days of age, and body weight gain, feed consumption, and feed efficiency were determined. In the first experiment, the chicks were fed diets with 23, 20, or 17% CP with minimum EAA set at 100% of the 1984 National Research Council (NRC) suggested requirements. Other groups were fed the 20% CP diet with EAA set at 93.5% or the 17% CP diet set at either 93.5 or 87.5% of the NRC requirements. In the second experiment, the 23% and 17% CP diets were fed, and glutamic acid was added at 3, 6, or 9% to provide the amino nitrogen equivalent of 23% protein with the minimum EAA set at 100% of 1984 NRC requirements. In the first experiment, body weight gain and feed efficiency, but not feed intake, were depressed by lowering CP content. Reducing the minimum EAA requirements in proportion to the reduction in CP failed to correct the difference in performance between the high and low CP diets. In Experiment 2, body weight gain and feed intake were reduced as intact CP decreased and glutamic acid increased, but feed efficiency was unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids, Essential↗

PubMed1987

Differential responses to dietary carbohydrates and fat of turkeys kept at various environmental temperatures.

Interactions between environmental temperature and dietary energy sources were evaluated in 6 to 9-wk and 9 to 12-wk-old turkeys using weight gain, feed efficiency, and carcass fat as response criteria. The dietary variables (soybean oil or glucose) were added in five or six increments at the expense of each other or of the fiber supplements, keeping the minima for protein and amino acid/energy constant. The resulting diets were fed to birds kept at 10 and 27 C. Duplicate experiments were conducted for each mode of dietary variable addition. Parallel increases in body weight gain and feed efficiency were obtained at the two temperatures when fat replaced carbohydrates or fiber, thereby raising dietary energy density. Some responses of weight gain and feed efficiency at the two temperatures were obtained also with a graded isocaloric addition of fat but the response was significant only at 27 C and not at 10 C. A greater response of gain and feed efficiency to energy supplied by dietary glucose was obtained at 10 C as compared with 27 C. Dietary fat supplementation resulted in increased deposition of carcass fat when given together with energy or isocalorically regardless of environmental temperature. Carcass fat was increased by glucose-energy at the low temperature only.

Adipose Tissue↗

PubMed2004

Effect of various levels of forage and form of diet on rumen development and growth in calves.

The effect of form of starter grain (coarse vs. ground) and inclusion of various levels of hay on body weight gain and rumen development was evaluated. Two experiments were conducted to determine the effect of form of diet and forage inclusion on intake, growth, feed efficiency, and weaning age in dairy calves. Diets consisted of commercial coarse starter (C), ground starter (G), coarse starter with 7.5% bromegrass hay of consistent particle size (8 to 19 mm) (H1), and coarse starter with 15% hay (H2). In experiment 1, intake was held constant across treatments until weaning, when feed was offered ad libitum. Calves receiving H1 and H2 were heavier and had greater body weight gain and greater feed efficiency than calves receiving C. There were no differences in intake. Total volatile fatty acid concentrations were higher, and the proportion of acetate was lower for calves fed G vs. C. In experiment 2, calves (n = 56) were offered diets on an ad libitum basis and weaned according to intake. There were no differences in body weight gain, average daily gain, feed efficiency, and age at weaning with respect to treatment. Starter and total dry matter intake tended to be greater in calves fed H1 and H2 vs. C. The addition of controlled particle size hay to diets of young calves appears to favorably alter rumen environment, resulting in increased intake and improved feed efficiency. Forage of a consistent particle size can be successfully utilized in starter rations of young calves.

3-Hydroxybutyric Acid↗

PubMed1996

Effects of dietary energy source and level on performance of newly arrived feedlot calves.

Three experiments were conducted with Simmental x Angus crossbred steers to determine the effects of energy source and level on performance of newly arrived feedlot calves. In trial 1, 68 steers (initial BW 215 +/- 9.4 kg) were used in a 2 x 3 factorial experiment to determine the effects of receiving diet and previous creep feed on performance. Diets were composed primarily of either corn silage, corn silage + alfalfa pellets + dry corn, or dry corn + alfalfa pellets. For the 41-d trial, calves fed the corn silage-based diet had greater (P < .05) ADG and feed efficiencies than calves fed the other two diets. In Trial 2, 60 steers (initial BW 212 +/- 4.6 kg) were used in a 28-d completely randomized design experiment to determine the effects of 16% CP receiving diets containing 70, 75, 80 or 85% concentrate on performance. There were no differences (P > .10) in ADG or feed efficiency due to dietary concentrate level. In Trial 3, 77 steers (initial BW 226.3 +/- 3.0 kg) were used in a 2 x 3 factorial experiment to determine the effects of dietary concentrate and protein levels on performance during a 28-d receiving period. The factors were concentrate level (70 vs 85% concentrate) and protein level (12.5%, 16%, or phase-fed at 23%, 17%, 14%, and 12.5% during wk 1, 2, 3, and 4, respectively). During wk 1, calves fed the 85% concentrate diet had greater (P < .01) DMI, ADG, and feed efficiency compared with 70% concentrate. Calves fed the 16% CP and phase-fed protein diets had greater (P < .01) DMI, ADG, and greater (P < .02) feed efficiency than calves fed the 12.5% CP diets. Receiving diets containing at least 16% CP and > 70% concentrates are beneficial to calves during the first week after feedlot arrival.

Aging↗

PubMed1994

Threonine requirement and threonine imbalance in broiler chickens.

Three experiments were conducted to determine the effect of excess dietary protein on threonine requirement of broiler chicks to 14 d of age (Experiments 1 and 2) and to determine the threonine requirement from 16 to 28 d of age (Experiment 3). Two dietary protein levels were used in Experiments 1 and 2:20% CP in a threonine-limiting basal diet containing wheat, peanut meal, and selected amino acids and 25% CP in the same basal diet supplemented with a mixture of amino acids lacking threonine. A threonine-limiting 25% CP diet based on corn, soybean meal, and amino acids was also included in Experiment 2. The threonine requirement of chicks from 16 to 28 d of age was determined using a single CP level (20%) in Experiment 3. Threonine requirements were estimated by broken line regression analysis of weight gain and feed efficiency. Threonine requirements based on weight gain were 7.7 and 6.7 g/kg of diet in Experiments 1 and 2, respectively, for chicks receiving the 20% CP diets. The requirements increased to 8.6 and 8.2 g/kg, respectively, for chicks fed the 25% CP diets based on wheat, peanut meal, and amino acids. The requirement for maximum weight gain of chicks fed 25% CP based on corn, soybean meal, and amino acids was 7.7 g/kg of diet. However, chicks ate more of this diet, and on an intake basis, the requirement of the chicks fed the 25% CP diets based on wheat and peanut meal or corn and soybean meal did not differ. Requirements based on feed efficiency were equal to, or less than, those based on weight gain in Experiments 1 and 2. Body moisture and fat contents were affected by dietary CP level (P < .01), ingredient composition (P < .01), and threonine content (P < .05). Estimates of threonine requirements based on regression analysis of plasma threonine concentrations were higher than those based on weight gain or feed efficiency. The threonine requirements of chicks fed a 20% CP diet from 16 to 28 d of age were 6.3 and 6.9 g/kg of diet based on weight gain and feed efficiency, respectively.

Animal Feed↗

PubMed1994

Dietary choline requirement of juvenile hybrid striped bass.

Two experiments were conducted to estimate the dietary choline requirement and to determine the effects of dietary choline on liver lipid deposition in juvenile hybrid striped bass (Monrone saxatilis x M. chrysops). Experimental diets contained 0.73 g total sulfur amino acids/100 g diet (0.47 g methionine + 0.26 g cyst(e)ine/100 g diet), thus meeting, but not exceeding, the requirement. Graded levels of choline bitartrate in Experiment 1 and choline chloride in Experiment 2 were added to the basal diet, resulting in eight dietary treatments in each experiment. Dietary treatments were 0, 250, 500, 1000, 2000, 4000, 6000 and 8000 mg choline/kg dry diet. Diets were fed for 12 and 10 wk in Experiments 1 and 2, respectively. Dietary choline concentrations significantly affected weight gain, feed efficiency, survival and total liver lipid concentrations in each experiment. Weight gain and feed efficiency were greatest in fish fed 500 mg choline/kg dry diet as choline bitartrate. Total liver lipid concentrations were variable but tended to be lowest in fish fed diets containing at least 2000 mg choline/kg diet. Survival was significantly lower in the group of fish fed 8000 mg choline/kg diet supplied by choline bitartrate. Weight gain and feed efficiency were greatest and total liver lipid concentration was lowest in groups of fish fed at least 500 mg choline/kg diet as choline chloride; survival was unaffected by dietary treatment. Therefore, choline chloride seems to be a better source of dietary choline than choline bitartrate and 500 mg choline/kg diet is adequate for maximum weight gain and prevention of increased liver lipid concentration in juvenile hybrid striped bass.

Animal Feed↗

PubMed1990

Effects of prenatal testosterone treatment and postnatal steroid implantation on growth performance and carcass traits of heifers and steers.

Two experiments were conducted to evaluate the effect of prenatal testosterone treatment in combination with postnatal steroid implantation (Exp. 1) and to assess the effect of time of prenatal testosterone treatment in conjunction with postnatal steroid implantation (Exp. 2) on animal performance and carcass characteristics. In Exp. 1, seventy-six pregnant cows were assigned randomly to a control group or implanted with testosterone propionate (TP) silastic implants between d 40 and 80 of gestation. Half the heifer calves were selected randomly to be implanted with 200 mg TP plus 20 mg estradiol benzoate (EB); the other half of the steer calves were implanted with 200 mg progesterone plus 20 mg EB on d 1 and 85 of the feedlot trial. Daily gain of heifers was increased 10.4% (P less than .08) due to prenatal testosterone treatment (P) and 16.4% (P less than .05) by postnatal steroid implantation (I). Feed efficiency was 12.9% greater (P less than .05) due to P and 9.5% greater (P less than .05) due to I. Prenatal testosterone treatment decreased (P less than .05) kidney, pelvic and heart fat and final yield grade but increased (P less than .05) ribeye area of heifers. Heifers had greater (P less than .07) liver weights per unit of carcass weight due to P. In Exp. 2, one hundred seventy-four pregnant cows were assigned randomly to a control group or implanted with TP silastic implants on d 42, 63, 84 or 105 of gestation. Half the heifer and steer calves were selected randomly to be implanted on d 1 and 112 of the feedlot trial. Time of P caused a quadratic effect (P less than .08) on birth weight of heifers. There was a quadratic effect (P less than .05) of time of P on daily gain and final weight per day of age of heifers. Feed efficiency of heifers was improved (P less than .05) due to P. Postnatal steroid implantation increased (P less than .05) daily gain and feed efficiency of heifers by 9.6% and 8.6%, respectively. No changes were observed in growth performance of steers due to P. Results from these two trials suggest that the combination of prenatal testosterone treatment and postnatal testosterone and estradiol implantation produced an additive improvement of daily gain, feed efficiency and carcass merit of heifers.

Adipose Tissue↗

PubMed2005

Impact of glutamine and Oasis hatchling supplement on growth performance, small intestinal morphology, and immune response of broilers vaccinated and challenged with Eimeria maxima.

Seven hundred and twenty hatchling broilers were allotted to 12 treatment groups. Groups 1 and 2 were fasted for 48 h posthatch; groups 3 and 4 were fasted for 48 h followed by ad libitum access to a 1% glutamine (Gln) diet; groups 5 and 6 had ad libitum access to a common diet; groups 7 and 8 had access to a 1% Gln diet posthatch; groups 9 and 10 were fed regular Oasis hatchling supplement; and groups 11 and 12 were fed Oasis sprayed with 1% Gln for the first 48 h posthatch. The birds in treatment groups 2, 4, 6, 8, 10, 11, and 12 were vaccinated with Eimeria maxima posthatch, and all birds were orally challenged with high dose E. maxima on d 22. During the first 2 wk, birds in group 7 had the highest gain and feed efficiency among treatments (P < 0.01). Compared with birds in the nonGln groups, birds in the Gln group had higher gain, feed efficiency, and livability (P < 0.05). Among the Fast (groups 1 to 4), Feed (groups 5 to 8), and Oasis (groups 9 to 12) groups, birds in the Feed groups had the highest gain during d 0 to 21 (P < 0.01). During d 22 to 28, birds in the Fast groups had the lowest BW and livability (P < 0.01), and the nonvaccinated birds had lower gain and feed efficiency relative to vaccinated birds (P < 0.01). Birds in the Feed and Oasis groups had higher villus height (VH) of mid small intestine than Fast groups at d 2 and 7 (P < 0.05), and nonvaccinated birds had higher VH than vaccinated birds (P < 0.01) at d 7 after hatch. On d 14, there were differences in serum interferon-gamma (P < 0.05) levels among treatments. During d 22 to 28, vaccinated birds had lower lesion scores in the mid small intestine than nonvaccinated birds (P < 0.01), and birds in the Feed or Oasis groups had lower lesion scores compared with the Fast groups (P < 0.02). These results indicated the importance of immediate access to feed posthatch, the beneficial effects of feeding Oasis hatching supplement and Gln after hatch, as well as the necessity of the vaccination program against coccidiosis challenge.

Animal Feed↗

PubMed1998

In ovo administration of recombinant human insulin-like growth factor-I alters postnatal growth and development of the broiler chicken.

Two experiments assessed the efficacy of in ovo administration of insulin-like growth factor-I (IGF-I) to enhance skeletal muscle development and improve feed efficiency of broilers. Hatching eggs were divided into three groups: uninjected control, vehicle-injected control, and recombinant human (rh) IGF-I (100 ng per embryo). Eggs in Experiment 1 were injected on Day 1, 4, or one of Day 7 through 18 of incubation. Growth rates for Days 1 and 4 resulted in the greatest response to treatment (P < 0.01, P < 0.06 respectively). Based on these results, Experiment 2 focused on Days 1 to 4 of incubation. Results from Experiment 2 showed that there was no significant difference in hatchability among control and rh IGF-I treatment groups. Injection on Day 3 resulted in the greatest response for increased live (P < 0.035) and leg (P < 0.02) weights in both sexes. Feed efficiencies of all rh IGF-I groups were significantly (P < 0.01) improved for the first 3 wk. In ovo administration of rh IGF-I on Day 3 increased feed efficiency (6.65%; P < 0.009) in pens of mixed-sex broilers. In addition, live weights (12.3%; P < 0.002), leg weights (11.7%; P < 0.01), breast weights (9.9%; P < 0.04), and heart weights (11.4%; P < 0.02) were increased in males. These results demonstrate that in ovo administration of rh IGF-I alters feed efficiency, growth, and tissue development. This finding lends itself to significant improvements in broiler production efficiency and profitability.

Animal Nutritional Physiological Phenomena↗