Nutrient digestibility and growth performance of pigs fed pearl millet as a replacement for corn.

Three experiments were conducted to determine the value of pearl millet grain, grown at either Purdue University or the University of Nebraska, as a substitute for corn in the diets of young pigs. In Exp. 1, 24 crossbred barrows, average initial weight of 20.7 kg, were used to evaluate nutrient digestibility of both sources of pearl millet compared with corn. Nitrogen digestibility was similar (P > .05) for corn and both sources of pearl millet. Energy and DM digestibilities were highest (P < .01) for corn, resulting in corn having a higher (P < .01) DE and ME value. Two 28-d feeding studies were conducted to evaluate the growth response of pigs when 0, 25, 50, 75, or 100% of corn was replaced with pearl millet (Exp. 2, Nebraska millet; Exp. 3, Purdue millet) and an equal-weight basis in nursery (Exp. 2) and growing (Exp. 3) diets. Experiments were designed as 2 x 5 factorials of sex and dietary treatment. In Exp. 2, 60, 10-kg crossbred pigs (barrows:gilts, 1:1) were used. During the 14-d period after weaning, and over the entire 28-d experimental period, no effect (P > .05) of dietary treatment on growth rate or feed intake was observed. However, from d 14 to 28, a quadratic response (P < .05) in growth rate and feed intake were observed from incremental substitution of pearl millet for corn. In Exp. 3, 50 crossbred pigs (barrows:gilts, 1:1) with an average initial weight of 24.3 kg were used. Rate of BW gain, feed intake, and gain:feed ratio were not affected (P > .05) by dietary treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Pearl millet in diets of white Pekin ducks.

In two 21-d experiments, the performance, nutrient utilization, and carcass composition of ducks fed diets containing pearl millet were compared with those fed diets containing corn. Corn, in diets at two protein levels (22 vs 18% in Experiment 1 and 22 vs 16% in Experiment 2), was replaced by pearl millet either on an equal-weight or isonitrogenous basis. During the first 2 wk of the first experiment, corn diets compared on an isonitrogenous basis were superior (P < .05) to the millet diets in promoting weight gain (666 vs 633 g per duck) and feed consumption (965 vs 914 g per duck); but when compared on an equal-weight basis, the millet diets were similar to the corn diets in promoting growth. No significant differences were observed for weight gain, feed consumption, or feed efficiency at the end of 3 wk. Over the 21-d study, the higher protein diets were more efficiently (P < .05) converted to weight gain than the lower protein diets (.63 vs .60 g gain:g feed). Carcass protein in ducks fed the corn diets was greater (P < .05) than in those fed the pearl millet diets. In Experiment 2, growth performance differences across dietary protein levels were similar to those in Experiment 1. However in contrast to Experiment 1, feed consumption was similar for corn and pearl millet diets (776 vs 786 g per duck, respectively), and ducks fed the corn diets gained less (P < .05) than those fed the pearl millet diets (590 vs 622 g per duck) during the first 2 wk of Experiment 2. Results of the nutrient utilization trial conducted at the end of Experiment 2 revealed that diets containing pearl millet were higher (P < .05) in AME than those containing corn (3,300 vs 3,100 kcal/kg). These results indicate that pearl millet has a higher energy value and appears to be at least equal to corn in promoting weight gains in ducks.

Comparative extraction methods for spectrophotometric analysis of uric acid in avian excreta.

Different extraction techniques were compared in uric acid analysis of avian excreta. These include five extraction reagents (0.1 M sodium hydroxide, 0.1 M glycine buffer, 0.068 m lithium carbonate, 0.136 M lithium carbonate and sodium borate buffer, pH 9.1). Each extraction reagent was used with four excreta sample weights (50,100,150 and 200 mg) for four extraction periods (10,20,30 and 40 min) in four extraction volumes (5,10,15 and 20 ml). Extraction with sodium hydroxide gave lower uric acid concentration; however, glycine buffer extraction gave uric acid concentration that was higher (P < 0.05) than extraction with lithium carbonate or sodium borate buffer. Uric acid concentration increased with increase in sample weight and decreased with decrease in reagent volume when extracted with glycine buffer. Filtration of sodium hydroxide and glycine buffer extract with 1-kDa low-binding regenerated-cellulose membrane did not alter uric acid extraction efficiency from avian excreta. Regardless of length of extraction period or volume, the recovery of crystalline uric acid following extraction with lithium carbonate or sodium borate buffer was not different from 100% when 100 mg sample or less was extracted. The optimum extractions condition 25 were 100 mg sample in 10 ml and 50 to 200 mg sample in 15 ml 0.068 M lithium carbonate or sodium borate buffer for 10 min at 99 degrees C.

Effect of beta, beta'-tetramethyl-substituted hexadecanedioic acid (MEDICA 16) on laying hen performance and egg yolk lipid composition.

1. beta, beta'-tetramethyl-substituted hexadecanedioic acid (MEDICA 16), an inhibitor of hepatic cholesterogenesis and lipogenesis in rats, was orally administered to 24-week-old White Leghorn hens for a period of 16 d. Hens were fed maize-soya-bean meal diets containing 0, 1.5, or 3.0 g MEDICA 16/kg. 2. Although MEDICA 16 did not affect egg weight, yolk weight, egg cholesterol content, or the efficiency of food utilisation, egg production was significantly reduced in birds fed 3.0 g MEDICA 16/kg compared to those fed the other two diets. 3. Total yolk monounsaturated fatty acids were significantly higher in eggs of hens fed both inclusion rates of MEDICA 16 compared to those of the control birds. In contrast, egg yolk total polyunsaturated fatty acid content and the ratio of polyunsaturated to saturated fatty acids were both inversely related to the dietary content of MEDICA 16. 4. These results suggest that MEDICA 16 primarily altered hepatic fatty acid metabolism, but not cholesterol synthesis, in laying hens.

Comparative effects of dietary tannins in ducks, chicks, and rats.

Studies were conducted to compare the effects of feeding high-tannin sorghum (HTS)- and low-tannin sorghum (LTS)-based diets suboptimal in protein to ducks, chicks, and rats. In the first series of experiments, Savanna (HTS) depressed both growth and feed efficiency of chicks and rats when compared with animals fed RS-610 (LTS). In contrast, ducks fed Savanna-based diets exhibited greater weight gains, but poorer feed efficiency values than birds fed RS-610. In a second series of experiments, Pioneer 8333 (LTS) and DeKalb BR-64 (HTS) sorghum-soybean meal diets were fed to chicks, ducks, and rats. As compared with animals fed 8333, BR-64 depressed both growth and feed efficiency of chicks and rats, but did not significantly affect either parameter in ducks. The lack of effect of HTS on duck growth may have been due to the formation of tannin-protein complexes upon exposure of the ground grain to water. This theory was based on the following observations: 1) ducks consumed water immediately after eating to facilitate swallowing the dry-mash diet; 2) a large amount of feed was deposited on the bottom of each water trough and subsequently consumed; and 3) ground HTS, which had been soaked for 4 h, had virtually no assayable tannin after drying. However, despite the marked reduction in assayable tannin content of treated HTS versus HTS that was dried only, the former material still depressed growth and feed conversion of rats. Thus, the lack of a growth-depressing effect of sorghum tannins in ducks fed dry-mash diets is both unique and unexplained.

Effects of dietary nonspecific nitrogen on [14C]glutamate and [14C]proline incorporation into bone proteins in chicks.

The incorporation of [14C]glutamic acid into EDTA-soluble and -insoluble calvaria protein in vitro and [14C]proline into EDTA-insoluble femur protein in vivo was determined in chicks fed inadequate and adequate levels of nonspecific nitrogen (glutamic acid). In each instance, the amount of amino acid incorporated into bone protein was reduced by the low level of nonspecific nitrogen. It was concluded that the high incidence of leg abnormalities observed in chicks fed purified diets containing adequate levels of indispensable amino acids but lacking in total nitrogen might be associated with an inability to form bone matrix protein.

Induction of proline-rich proteins in hamster salivary glands by isoproterenol treatment and an unusual growth inhibition by tannins.

Treatment of hamsters with the beta-agonist isoproterenol caused a dramatic increase in a series of unusual proteins in the parotid and submandibular glands. These proteins are acid soluble and they contain high amounts (mol%) of glutamate plus glutamine (30-35), proline (23-30), and glycine (12-25). Three proteins (HP45, HP43a, and HP43b) were isolated from trichloroacetic acid extracts of parotid glands of isoproterenol-treated hamsters. The basic protein (HP45) was not retained by DEAE-cellulose and did not contain phosphate or carbohydrate. Two acidic proteins (HP43a and HP43b) had the same apparent molecular weight on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, but these were separated by DEAE-cellulose chromatography. HP43a and HP43b contained 4.3 and 5.7 phosphate residues/mol of protein, respectively. Levels of mRNAs encoding this series of proteins showed striking increases following isoproterenol treatment as determined by cell-free translations and Northern analysis. Feeding tannins to rats and mice mimicks the effects of isoproterenol treatment on the parotid gland (Mehansho, H., Hagerman, A., Clements, S., Butler, L., Rogler, J., and Carlson, D.M. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 3948-3952; Mehansho, H., Clements, S., Sheares, B. T., Smith, S., and Carlson, D. M. (1985) J. Biol. Chem. 260, 4418-4423]. However, hamsters on a high tannin diet (2%) did not respond like rats and mice and instead displayed an unusual growth inhibition. Weanling hamsters maintained on a 2% tannin diet initially lost weight for 3 days and then failed to gain weight for up to 6 months when kept on this diet. Essentially a normal growth rate was observed when the tannin-fed hamsters were switched to a normal diet.

Response of growth-selected Japanese quail lines to tannin levels in grain sorghum diets with suboptimal protein.

Growth of selected lines of Japanese quail fed grain sorghum diets was evaluated. Suboptimal protein levels (23 and 25%) were used in conjunction with two varieties of sorghum differing in tannin content (.02 vs. 6.06%). Chicks of three related lines of quail differing in growth rates and mature body sizes were fed the diets from 0 to 28 days of age. Growth was significantly reduced (14 and 6%) by substitution of high tannin sorghum for low tannin sorghum in the 23 and 25% protein diets, respectively. No line X diet interaction was observed.

Effects of D-amino acids on growth rate and kidney D-amino acid oxidase in chicks.

Studies were conducted on the effects of feeding D-amino acids on growth rate and D-amino acid oxidase (DAAO) in chick kidney. The crystalline amino acid (AA) diet provided seven amino acids either in the L-form or the DL-form at two concentrations (DL- or .5 DL-AA diets) with all diets containing equal amounts of L-amino acids. Weight gains of chicks fed the DL-AA diet were consistently lower than those fed the L- or .5 DL-AA diet. Kidney DAAO activity was significantly higher in chicks fed either the DL-AA or .5 DL-AA diet as compared with the L-AA diet. Kidney DAAO activity was essentially the same in chicks fed the DL- and .5 DL-AA diets. Increasing the nonspecific nitrogen in the diet had no effect in alleviating growth depression of the DL-AA.

Methionine requirement of male white Pekin ducklings.

Two experiments were conducted to determine the methionine (Met) requirement of male White Pekin ducklings. In each study, day-old ducklings were raised in electrically heated battery brooders and fed a corn-peanut meal basal diet (dry mash) supplemented with either 0, .06, .12, .18, .24, or .30% L-Met. Based on the analysis of corn and peanut meal, the basal diet contained 22% crude protein .268% Met, and .284% cystine (Cys). The energy content of the basal diet was calculated to be 2914 kcal ME/kg. Regression analysis of 12- day weight gain data pooled across experiments indicated a quadratic trend. When the quadratic model was solved for 95% of maximum growth, a Met requirement of .422% was predicted (r2 = .49). Analysis of the pooled weight gain data by the broken-line method yielded a requirement estimate of .382% (r2 = .50). Therefore, the duckling's calculated Met requirement most likely lies between .382 and .422% (.666 and .706% total sulfur amino acids, respectively). This .04% discrepancy between models for predicting the duckling's Met requirement is probably of minor practical significance, considering the variability of Met and Cys contents of feedstuffs and the fact that corn-soy diets are usually supplemented with a source of Met activity that includes a margin of safety.

Dietary self-selection and the regulation of protein and energy intake in chicks.

Studies were conducted to determine whether chicks could regulate their protein intake independent of total energy intake in self-selection feeding trials. Day-old White Mountain cockerels were reared in electrically-heated battery brooders and given access to either a 23% protein control ration (no choice) or two diets containing 10% or 60% protein with or without supplemental amino acids. The latter were added to either improve the dietary amino acid balance or to alter plasma and brain levels of free large neutral amino acids (tryptophan, isoleucine, leucine, valine, phenylalanine, and tyrosine) which have been implicated in the neuroregulation of feed intake. Both feed and water were provided ad lib, and the location of the feed troughs within each pen were changed daily. Body weights and feed intakes were measured daily, and total calorie and protein intakes were calculated. Chicks offered 10% and 60% protein diets with no supplemental amino acids exhibited reduced weight gains and markedly higher protein intakes as compared to birds fed either the control ration or those given a choice between 10% and 60% protein diets supplemented with methionine. The higher protein consumption by chicks fed the unsupplemented diets most likely was a result of an attempt to compensate for a dietary methionine deficiency. Chicks fed the 10% and 60% protein diets supplemented with amino acids grew at a slower rate than those fed the 23% protein control diet. In general, plasma and brain data did not support a proposed relationship between certain large neutral amino acid ratios and protein or energy intake.

Effects of a nonspecific nitrogen deficiency on growth rate and leg problems in chicks.

Five experiments were conducted using crystalline amino acid and semipurified diets containing adequate levels of all indispensable amino acids, vitamins, and minerals to study the effects of dispensable amino acids on growth and the incidence of leg abnormalities of male chicks. Purified diets containing 5% L-glutamic acid as the sole source of nonspecific nitrogen resulted in poor growth and feed efficiency, high mortality, and a high incidence of leg abnormalities with many severe cases of this condition. Increasing the dietary level of L-glutamic acid to 10% of the purified diet or supplementing the 5% L-glutamic acid diet with 2.40% glycine or 1.68% L-serine improved weight gain but did not eliminate the leg conditions. Higher L-serine (3.36%) resulted in a growth depression, indicating that this level was toxic to the birds. It was necessary to increase the dietary L-glutamic acid to 12.5% to reduce the incidence of leg problems to a minimum. Plasma dispensable amino acid levels (aspartic acid, glutamic acid, and alanine) paralleled the levels of L-glutamic acid in the diets fed to the chicks. Plasma serine and glycine levels were increased by adding either serine or glycine, but the magnitude of the increase of either amino acid was greatest with the addition of that amino acid to the diet. Plasma proline concentrations increased when chick diets were supplemented with high levels of glycine (2.4%), serine (3.36%), or glutamic acid (9.7%) in relation to those supplemented with only 5% L-glutamic acid. Feeding an intact protein (isolated soybean protein) diet did not alleviate leg disorders, although it did improve weight gain.

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.

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

A study was conducted to investigate the effect of sorghum grain tannins on the performance of laying hens. A total of 144 White Leghorn hens were arrayed according to egg production during a 10-day preexperimental period into eight groups consisting of four nutritional treatments in each of two constant temperature environments (22 and 28 C). The nutritional treatments consisted of low (RS610) and high (Savanna) tannin sorghum grains compared isonitrogenously within a protein level at two protein levels (11.5 and 14.5%) in sorghum-soybean meal diets. These diets were fed for an experimental period of 6 weeks. Egg production and feed efficiency were reduced and weight loss was increased by 11.5% protein as compared with 14.5% protein. Tannin significantly reduced egg production and feed efficiency at both protein levels while egg specific gravity and shell thickness were adversely affected only at the lower level of protein. Egg weight and weight loss of hens were not affected by tannin. Except for weight loss, all parameters were slightly reduced by the higher temperature. At the end of the experiment, all hens were placed on a commercial laying ration for a 31-day period. Recovery from the treatment effects was evidenced by the similar egg production, body weight, egg weight, and shell characteristics among the previous treatments at the end of this period.

Effects of sorghum grain tannins and dietary protein on the activity of liver UDP-glucuronyltransferase.

The activity of liver microsomal UDP-glucuronyltransferase (EC 2.4.1.17), an enzyme known to detoxify phenolic compounds, was measured in chicks and rats fed high- (HTS) and low-tannin sorghums (LTS). In an initial investigation, activity was significantly elevated in chicks fed HTS-soybean meal diets over those fed the LTS control diet. Other studies were designed to differentiate between the effects due to tannin and those resulting from a protein deficiency which had previously been reported to increase the activity of this enzyme. In general, only a relatively small part of the increased activity observed by feeding HTS to chicks could be attributed to a tannin-induced protein deficiency. The same phenomenon of elevated activity produced by feeding HTS to chicks was not observed in the rat. These results would suggest that sorghum tannins, or their breakdown products, are absorbed and activating UDP-glucuronyltransferase in the chick, but not the rat.

Modulation of proline-rich protein biosynthesis in rat parotid glands by sorghums with high tannin levels.

Feeding of sorghum with a high level of tannin (high-tannin sorghum) to rats caused changes in gene expression in parotid glands similar to isoproterenol treatment. Within 3 days the parotid glands were enlarged about 3-fold and a series of proline-rich proteins were increased about 12-fold. Unlike isoproterenol treatment, no changes were observed in the submandibular glands, and a Mr 220,000 glycoprotein in parotid glands was not induced. Amino acid analyses, electrophoretic patterns, and cell-free translations of mRNAs all confirmed that the proline-rich proteins induced by feeding high-tannin sorghum were identical to those induced by isoproterenol treatment. Binding curves for proline-rich proteins to tannins showed affinities 10-fold greater than bovine serum albumin and tannins.

Effect of thiouracil on response to heat stress of White Leghorn lines selected for fast and slow gain in two temperatures.

Four lines of White Leghorns previously selected for fast and slow gain from 5 to 9 weeks of age in a hot (32.2 C) and in a cold (21.1 C) selection environment were grown from 5 to 9 weeks in the same two temperature environments. Samples of 32 females from each line of the third generation grown in each temperature environment from 5 to 9 weeks of age were divided into two groups; one received .2% thiouracil in the diet for a 5-day period and the other did not. The temperature was then increased to 40.6 C until 52.8% of all birds had died. The percentages of mortality of lines, rearing environments, and thiouracil treatments were then analyzed. An increase of 64.8% mortality from acute heat stress for birds reared in the cold environment was significant, but the differences among the four selected lines were not. The presence of thiouracil in the diet significantly reduced mortality from heat stress by 16.4%. There were no significant interactions between thiouracil treatments and selected lines or rearing environments.

Partial alleviation of phenylalanine toxicity in the chick by supplemental dietary tryptophan.

Studies were conducted to determine the physiological effects of feeding diets containing high levels of phenylalanine to chicks. Marked reductions in weight gain and feed conversion were observed in birds fed a diet containing 2.52% L-phenylalanine and .47% L-tyrosine. Excess dietary phenylalanine caused elevations of phenylalanine and tyrosine in serum and brain, whereas cerebral concentrations of free isoleucine, leucine, and valine were generally decreased. Supraoptimal amounts of glycine, arginine, and tryptophan were fed in an attempt to alleviate the toxic symptoms observed in birds fed high phenylalanine diets. Only tryptophan supplementation proved successful in partially alleviating the growth-depressive effects of phenylalanine toxicity. Both serum and brain levels of tryptophan were increased by tryptophan supplementation. Results of two radiotracer studies with 14C-tryptophan suggested that brain uptake of tryptophan was inhibited by hyperphenylalaninemia.