Increased BW Gain Research Articles

Improving Phytate Phosphorus Availability in Corn and Soybean Meal for Broilers Using Microbial Phytase and Calculation of Phosphorus Equivalency Values for Phytase

Two experiments were conducted to determine the effectiveness of Natuphos® phytase for improving P availability of soybean meal-based semi-purified diets (SP, Experiments 1 and 2) and corn-soybean meal-based diets (CS, Experiment 2) fed to broilers (1 to 21 d). There were 360 and 288 birds fed the SP diets in Experiments 1 and 2, respectively, and 288 birds were fed the CS diets in Experiment 2. Phosphorus equivalency values for phytase were calculated. The basal diets were formulated to contain 0.27% nonphytate P (nP); the SP basal diet contained 0.45% total P (tP) that included 0.17% P as defluorinated phosphate; the CS basal diet contained 0.51% tP that contained 0.12% P as defluorinated phosphate. Both basal diets were supplemented with defluorinated phosphate to provide 0.36, 0.45, or 0.54% nP or with 350, 700, or 1,050 U of phytase/kg diets. Supplementing defluorinated phosphate and phytase linearly increased BW gain (P < 0.001), feed intake (P < 0.001), and percentage ash of dried toes (P < 0.01). Phytase addition increased apparent retention of P (P < 0.02), Ca (P < 0.005 in Experiment 2), and N (P < 0.06 in Experiment 2 for CS), increased apparent digestibility of DM (P < 0.04), and linearly decreased (P < 0.005) P excretion. In comparison to the 0.45% nP diet, P excretion was reduced 42 to 51% by addition of phytase. The addition of defluorinated phosphate linearly decreased apparent retention of P (P < 0.02) and Ca (P < 0.005 in Experiment 2), and increased P excretion (P < 0.007). The average of released P by phytase calculated by solving nonlinear or linear response equations of P and phytase levels for SP diets in Experiments 1 and 2 gave a P equivalency value of 1 g P = 1,146 U of phytase. The P equivalency value for CS diets fed only in Experiment 2 was 785 U of phytase = 1 g P as defluorinated phosphate. These studies show that microbial phytase is effective for improving P availability and for decreasing P excretion. Added phytase can also increase Ca and N retention.

Response of Turkey Poults to Tiered Levels of Natuphos® Phytase Added to Soybean Meal-Based Semi-Purified Diets Containing Three Levels of Nonphytate Phosphorus

A 3-wk feeding trial using 920 day-old turkey poults was conducted to evaluate the addition of seven levels of phytase (Natuphos®; 0, 200,400,600,800,1,000, and 1,200 U/kg of diet) to diets containing three levels of nonphytate P (nP) (.27, .36, and .45%). A positive control diet contained .60% nP. Semi-purified basal diets contained soybean meal as the only protein source. The increase in BW gain from added phytase was greatest for the lowest nP diet (nP by phytase interaction, P < .001). At .27% nP, gains improved (P < .001) to 800 U of phytase/kg of diet and then reached a plateau. At .36 and .45 % nP, increases in gains were observed only for 200 U of phytase/kg of diet. The highest phytase addition to .36 and .45% nP diets produced gains equal to those of the positive control diet. Feed intake increases paralleled those of BW gains. Gain:feed was lowest for the .27% nP diets without phytase, but improved (P < .001) to 800 U of phytase/kg of diet and then reached a plateau. The high incidence of leg disorders and high mortality (40%) observed for the poults fed the .27% nP diet without added phytase declined with the addition of 200 to 400 U of phytase/kg of diet. Ash percentage of toes and tibias increased as the levels of nP (P < .001) and phytase (P < .01) increased; the magnitude of the response to phytase decreased as nP in the diet increased, resulting in an nP by phytase interaction (P < .001). Tibial shear force and stress responded in a similar manner to increasing levels of nP and added phytase. Results show that 652 U of microbial phytase is equivalent to 1 g of P from defluorinated phosphate in turkey starter diets using soybean meal as the only source of phytate P. The response per 100 U of phytase decreased as the total amount of phytase added was increased.

Divergent Selection for Growth in Japanese Quail Under Split and Complete Nutritional Environments.: 8. Progress from Generations 18 through 30 Following Change of Selection Criterion

Following 17 generations of divergent selection for 4-wk BW under split- (SD) and complete- (CD) diet environments, two sublines were established from high (H-SD and H-CD) BW lines. Subline H-SDG derived from the H-SD line was selected for BW gain from 2 to 4 wk under the SD environment, whereas Subline H-CDG derived from the H-CD line was similarly selected under the CD environment. These two sublines were maintained and reproduced simultaneously with H-SD, L-SD, H-CD, L-CD lines from Generation 18 through 30. The purpose of changing the selection criterion was to investigate genetic variation in BW gain independent of changes that occur immediately following hatch.Selection progress and heritabilities (≈ .3) in BW lines (H-SD, H-CD, and L-SD) were similar from Generation 18 through 30. However, progress and heritability (≈ .1) was not as great in the L-CD line. These responses indicate that considerable additive genetic variation for 4-wk BW remains in these lines. Selection for increased BW gain from 2 to 4 wk in both sublines (H-SDG and H-CDG) resulted in smaller BW at 2 wk of age than did selection for 4-wk BW. Under the SD environment, H-SDG quail were smaller at 4 wk than H-SD quail following 12 generations of selection, whereas under the CD environment, H-CDG quail were larger than H-CD quail. Results indicate that selection for BW gain was more effective under the CD than SD environment and that the lack of improvement in 2-wk BW accompanying the increase in BW gain may adversely influence the potential benefits obtainable from selection for gain.

Effects of supplementation on intake, growth rate, and fleece production by female Angora kid goats grazing rangeland.

Ninety-eight and 88 female Angora kid goats (6 mo of age) were grazed/browsed on Edwards Plateau rangeland in 92- and 88-d trials in 1989 and 1990, respectively. The goats were either not supplemented (negative control, NC) or fed isoenergetic amounts of corn (C), a corn/cottonseed meal/molasses mixture (C/CSM), or a corn/cottonseed meal/fish meal/molasses mixture (C/CSM/FM). The C/CSM and C/CSM/FM supplements provided equal CP but different amounts of ruminally undegraded protein (UDP). The goats were allowed to graze/browse in a common pasture and were separated into treatment groups three times each week for feeding. Intakes of supplement and forage were measured using a dual-marker technique. Forage intake was not increased with supplemental feeding (P = .21), but tended (P = .08) to be greater with high-protein supplements than with C. Total digestible DMI was greater (P < .01) for supplemented goats and was not affected by supplement type. Supplemental feeding increased BW gain (P < .01) and clean fleece weight (CFW; P < .01). High-protein supplements increased BW gain (P < .01), CFW (P = .07), fiber diameter (FD; P < .01), and staple length (P < .01) compared with C. Greater amounts of UDP (C/CSM/FM) did not increase BW gain (P = .99) but tended to increase CFW (P = .12) and FD (P = .15). Supplemental feeding increased total digestible DMI by partial substitution (corn) for forage or addition (high-protein supplements) to forage, and both energy and protein increased BW gain and CFW and influenced mohair traits.

Plasma concentrations of thyroid hormone in steers treated with Synovex-S and 3,5,3'-triiodothyronine.

This experiment examined the effect of daily administration of 3,5,3'-triiodothyronine (T3) on plasma profiles of T3, thyroxine (T4), 3,3',5'-triiodothyronine (reverse T3; rT3) and thyrotropin (TSH) in beef steers in which protein accretion was increased by using implants of Synovex-S (SYN). Twenty-four Angus-Hereford steers (302 +/- 16 kg) were individually fed a diet of a corn-based concentrate and silage mixture for 56 d at equal energy intake per steer (ME/unit BW.75). A 2 x 2 factorial arrangement of treatments was used in which treatments were SYN ear implants (200 mg of progesterone and 20 mg of estradiol benzoate) or no implants and s.c. injections of T3 in polyethylene glycol (2 micrograms of T3/kg BW every 48 h) or no injections of T3. Blood samples were collected every 2 wk. Plasma T3 concentration during the experimental period was increased in T3-treated steers (3.0 +/- .1 vs 2.2 +/- .1 ng/mL, P < .01) and was decreased in SYN-implanted steers (2.4 +/- .1 vs 2.7 +/- .1 ng/mL, P < .01). Plasma T4 and rT3 concentrations were reduced (22 +/- 4 vs 75 +/- 2 and .04 +/- .01 vs .12 +/- .01 ng/mL, respectively, P < .01) in T3-treated steers. Concurrently, plasma TSH concentration was decreased in T3-treated steers (.37 +/- .01 vs .51 +/- .02 ng/mL, P < .02). Synovex-S increased BW gain (21.0%, P < .01) and protein gain (35.6%, P < .01) compared with that of nonimplanted steers. Body weight gain and protein gain were not affected by treatment with T3.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Extra Energy as Fat or Milk Replacer Solids in Diets of Young Dairy Calves on Growth During Cold Weather

The effects of feeding two levels of supplemental fat and extra milk replacer solids on Holstein calves housed in hutches during the winter were investigated. Fifty calves (10 per treatment) were assigned to the following dietary treatments: 1) milk replacer (control) reconstituted to 12.5% DM fed at 10% of BW (adjusted weekly), 2) same as treatment 1 plus 113 g/d of supplemental fat, 3) milk replacer reconstituted to 15% DM and fed at 10% of BW (adjusted weekly), 4) same as treatment 1 plus 226 g/d of supplemental fat, and 5) milk replacer reconstituted to 15% DM fed at 14% of BW (adjusted weekly). Half the amount of milk replacer consumed during wk 4 was fed during wk 5, and calves were weaned to dry feed at 35 d of age. A pelleted starter was offered for ad libitum intake throughout the 42-d trial. Gains in BW were greater for calves fed 226 than 113 or 0 g/d of supplemental fat (d 3 to 28). Calves fed milk replacer reconstituted to 15% DM at 14% of BW had greater BW gains during d 3 to 28 than control. Starter consumption was similar between groups receiving 113 and 0 g/d of fat supplement but lower in the group fed 226 g/d. Extra milk replacer solids in diet increased fecal scores to levels greater than those of calves in other groups. The benefit of fat supplementation of milk replacers was manifested as increased BW gain during the 1st mo of life.

Influence of thyroid status regulation and Synovex-S R implants on growth performance and tissue gain in beef steers

The separate and combined effects of Synovex-S R (SYN) ear implants and thyroxine (T 4)-5′-monodeiodinase inhibition (Trial 1) and T 3 injection to create a mild elevation in circulating T 3 concentrations (Trial 2) on BW gain and composition of gain were studied. Trial 1 used 24, 285-kg Angus steers in two experimental phases. Low-level feeding of propylthiouracil (PTU, 1.5 mg/kg BW daily) was used to achieve inhibition of T 4-5′-monodeiodinase activity (TMA). Twelve steers received neither treatment (control) and 12 received SYN+PTU (hypothesized to maximize weight gain) from 0 to 56 d (phase 1) in a single factor treatment comparison. Subsequently, PTU was fed to six control steers and not fed to six of the original SYN+PTU steers from 56 to 175 d (phase 2) in a 2 × 2 arrangement of treatments. Trial 2 used 24, 302-kg Angus-Hereford steers. Treatments were without or with SYN and without or with sc injections of T 3 in polyethylene glycol (2 μg/kg BW every 48 hr) in a 2 × 2 factorial arrangement of treatments. In both trials, all steers were individually fed a diet of a corn-based concentrate and silage mixture at an equal metabolizable energy intakes per unit of metabolic body weight (.25 Mcal/kg BW .75). Measurements of daily dry matter intakes, weekly BW, 2-d estimates of empty body components (measured by urea dilution), final TMA (trial 1) and plasma thyroid hormone concentrations were obtained. In both trials, SYN increased BW gain and protein accretion. Partial inhibition of TMA (Trial 1) tended (P>.10) to increase BW gain in both nonimplanted and implanted steers, increase fat deposition in nonimplanted and implanted steers, increase fat deposition in nonimplanted steers and increase protein deposition in implanted steers. Injections of T 3 (Trial 2) tended (P>.10) to reduce both BW and protein gains. The results suggest that the effects of TMA inhibition and T 3 injection are additive with SYN and that T 3 is not a limiting factor to protein deposition in SYN-treated steers.

Relative Value of Fish Meal Versus Solvent Soybean Meal for Lactating Dairy Cows Fed Alfalfa Silage as Sole Forage

Fish meal was compared with soybean meal in three trials. In trial 1, 20 early lactation cows fed 70% alfalfa silage received an average .46kg of CP/d from either source in 2 × 2 Latin squares. Rumen protein escapes estimated in vitro were 37% (soybean meal) and 60% (fish meal). Fish meal increased BW gain, milk protein content, yield of milk, FCM, protein, and lactose; lowered rumen propionate; and increased rumen acetate:propionate. In trial 2, 32 midlactation cows fed 89% alfalfa silage were divided into two groups of 16 and supplemented with 0, 1.5, 3.0, or 4.5% CP from either soybean meal or fish meal in 4 × 4 Latin squares. Rumen protein escapes estimated in vitro were 31% (soybean meal) and 67% (fish meal). There were linear increases in BW gain and in yield of milk. protein, lactose, and SNF with either protein but no differences between proteins. In trial 3, 32 early lactation cows fed 56% alfalfa silage received no protein supplement or an average .55kg CP/d from soybean meal, high solubles fish meal, or low solubles fish meal in 4 × 4 Latin squares. Rumen protein escapes estimated in vitro were 27% (soybean meal), 43% (high solubles fish meal), and 63% (low solubles fish meal). Protein increased yield of milk, FCM, fat, protein, lactose, and SNF versus no supplement. Milk protein content increased about .1 percentage unit with both fish meals. Protein yield increased 61, 95, and 130 g/d with soybean meal, high solubles fish meal, and low solubles fish meal versus no supplement. In all trials, fish meal slightly reduced milk lactose content but did not alter milk fat content. Results indicated that greater rumen escape of fish meal protein, relative to soybean meal, increased efficiency of protein utilization in lactating cows fed alfalfa silage.

Cholesterol Concentration of Egg Yolk and Blood Plasma and Performance of Laying Hens as Influenced by Dietary α-Ketoisocaproic Acid

Experiments were conducted to determine the effect of supplemental α-ketoisocaproic acid (KIC) or Leu on layer performance and plasma and egg cholesterol levels. In the first experiment, 0, .09, or .27% KIC and .09 or .27% Leu were fed to 62-wk-old laying hens. In a second experiment, the same levels plus another level of .54% KIC and .54% Leu were fed to 32-wk-old hens for an 8-wk period. The basal diet or the basal diet supplemented with .27% KIC or .27% Leu were continued for 20 wk to determine the long-term effects of these supplements. In a third experiment, hens were fed 0, .1, .2, or .4% KIC for 8 wk.The addition of KIC and Leu to the hen diets did not affect percentage egg production, egg weight, shell thickness, or Haugh units. In Experiment 1, .27% KIC and .09% Leu significantly increased BW gain. Neither KIC or Leu significantly affected BW gain in Experiment 2 when measured at 8 or 28 wk. In the third experiment, diets supplemented with KIC increased significantly BW gain.In Experiment 1, .09% KIC and .09% Leu significantly reduced egg cholesterol at 4 wk. After 8 wk, .27% KIC reduced egg cholesterol significantly below the controls. No effect on plasma or egg cholesterol was observed in Experiments 2 and 3.

Cimaterol reduces beta-adrenergic receptor density in rat skeletal muscles.

Interactions between the beta-adrenoceptor agonist cimaterol and beta-adrenoceptors on rat skeletal muscle membranes were examined in two studies. In Exp. 1, muscle samples from eight Sprague-Dawley rats (female, approximately 200 g) were used for competition binding and autoradiographic studies using [125I]cyanopindolol (ICYP) as a radioligand. The affinities or dissociation constants for binding (KD values) for cimaterol in plantaris and soleus muscles were .68 and .92 microM, respectively. Muscle areas stained for succinic dehydrogenase had propranolol-resistant ICYP binding sites; cimaterol did not seem to compete for these sites. In Exp. 2, 60 Sprague-Dawley rats (female, approximately 218 g) were fed 0 or 10 ppm of cimaterol in rat diet that was ground. Groups were killed after 1, 3, 7, 14, or 28 d of treatment. Cimaterol increased BW gain up to 14 d after commencement of treatment, with little or no improvement thereafter. Enhanced weight gain in skeletal muscles also occurred up to 14 d of cimaterol treatment. Densities of beta-adrenoceptors in plantaris and soleus muscle membrane homogenates were estimated using a radioligand binding assay with ICYP. A significant reduction in the number of binding sites (Bmax) was observed after 3 d of cimaterol treatment in plantaris muscle without a change in the KD of ICYP binding. The percentage reductions in Bmax were 26.8, 42.2, 37.7, and 37.8% at 3, 7, 14, and 28 d after cimaterol administration, respectively. In the soleus muscle, significant reductions (44.1 and 29.8%) in Bmax were observed after 3 and 14 d of cimaterol treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Dietary Aluminum Sulfate on Calcium and Phosphorus Metabolism of Broiler Chicks

The effect of dietary aluminum sulfate on Ca and P metabolism was studied using 1-day-oldmale broiler chicks. In Experiment 1, practical diets providing .90% Ca plus .45% available P (Pav), .90% Ca plus .78% Pav, 1.80% Ca plus .45% Pav, or 1.80% Ca plus .90% Pav were fed with 0 or .392% Al as aluminum sulfate for 21 days. The control diet (.90% Caplus .45% Pav) without added A1 was fed to all chicks during Days 22 to 49. In general, Al significantly (P<.05) decreased BW gain, feed intake, gain:feed ratio, plasma inorganic P (Pi), tibia breaking strength, tibia weight, percentage of tibia ash, and plasma Zn, measured at Day 21. Elevating Pav increased BW gain, feed intake, gain:feed ratio, tibia weight and plasma Zn, and decreased plasma total Ca in the presence of .392% Al plus 1.80% Ca. Plasma Pi, tibia breaking strength, and percentage of tibia ash were increased by raising dietary Pav in the presence of .392% Al with either level of Ca. Negative effects of dietary Al on feed intake and BW persisted through Day 49.In Experiment 2, a control diet (.90% Ca, .45% Pav) was fed for ad libitum access either alone or supplemented with .2% Al as aluminum sulfate or with an equivalent amount of sulfate provided by potassium sulfate. The control diet was also pair-fed to chicks given .2% Al. Dietary Al significantly depressed weight gain, feed intake, gain:feed ratio, and plasma Pi. No effects were noted due to adding potassium sulfate to the diet. Pair-feeding the control diet decreased weight gain, feed intake, and tibia weight, but not plasma Pi. These results indicate that the toxic effect of aluminum sulfate is due to the aluminum and not the sulfate ions. The influence of aluminum on growth is mainly due to depressed feed intake, while the altered Ca and P metabolism results from a direct effect of Al per se.