Effect of feeding low-oil distillers dried grains with solubles on the performance of broilers.

Manufacturers of distillers dried grains with solubles (DDGS) are changing practices to extract corn oil from DDGS in the process of ethanol production. The resulting product is called low-oil DDGS (LO-DDGS) and may be included in broiler diets. Two LO-DDGS and one unextracted DDGS were used in a broiler performance trial to determine maximum levels of inclusion without detrimental effects. Corn- and soybean meal-based mash diets were used with different DDGS samples included at 10 or 20%. Six hundred thirty Cobb 500 male by-product chicks were randomly assigned to 6 replicate pens containing 15 chicks each and fed diets from 0 to 18 d of age. There was a significant interaction between source and level on BW at d 11 and 18 when 10 and 20% of LO-DDGS was included compared with the control group. There was also a significant effect of source and level interaction on BW at d 18 (P < 0.05). Feed efficiency from d 0 to 18 was improved when 10% LO-DDGS was used compared with 20% inclusion. Abdominal fat pad weights were higher when LO-DDGS samples were included at 10 or 20% compared with the control group. There was a significant effect of DDGS source and level on fat pad weights (P < 0.05). Producers may achieve an increase in performance when including 10% LO-DDGS in broiler diets. Up to 20% inclusion levels may have no detrimental effects on performance parameters compared with a standard corn-soybean diet.

Antimicrobial activity of lupulone against Clostridium perfringens in the chicken intestinal tract jejunum and caecum.

OBJECTIVES: Owing to the spread of antibiotic resistance among human infectious agents, there is a need to research antibiotic alternatives for use in animal agricultural systems. Antibiotic-free broiler chicken production systems are known to suffer from frequent outbreaks of necrotic enteritis due in part to pathogenic type A Clostridium perfringens. Hop (Humulus lupulus) bitter acids are known to possess potent antimicrobial activity. Lupulone was evaluated for in vivo antimicrobial activity to inhibit C. perfringens in a chick gastrointestinal colonization model. METHODS: Using a week-2 per os inoculated C. perfringens chicken colonization model, C. perfringens counts in mid-intestinal and caecal contents were compared between chickens administered lupulone at 62.5, 125 and 250 ppm in drinking water versus 0 ppm control. Results At day 22, post-hatch intestinal C. perfringens counts of lupulone-treated chickens were significantly lower (P < 0.05) than water-treated control groups in both jejunal and caecal sampling sites across all lupulone dosages tested. CONCLUSIONS: Lupulone administered through water inhibits gastrointestinal levels of inoculated pathogenic clostridia within the chicken gastrointestinal tract. Lupulone was effective within the chemically complex mixture of material within the gastrointestinal tract, thereby making this agent a target of further research as an antibiotic alternative for this and possibly other intestinal infections.

Relative toxicity of gossypol enantiomers in laying and broiler breeder hens.

Gossypol, a natural component of cottonseed meal, exists in positive (+) or negative (-) enantiomeric forms, and their levels and ratio could be altered by developing new genetic strains of cotton. Two experiments were conducted to determine the relative toxicity of the individual gossypol enantiomers in laying and broiler breeder hens. In the first experiment, 25 individually caged Hy-Line W-36 forty-three-week-old laying hens were fed a standard corn-soy diet supplemented with either no gossypol or the individual enantiomers at 200 and 400 mg/kg of diet for 20 d (5 hens/treatment). In the second experiment, 15 individually caged Cobb 500 fast-feathering 44-wk-old broiler breeder hens were fed a standard corn-soy-wheat middlings diet supplemented with either no gossypol or the individual enantiomers at 400 mg/kg of diet for 18 d (5 hens/treatment). In both experiments, feed intake, egg production, and egg weight were determined daily. All eggs were individually opened and scored for yolk discoloration. At the end of both experiments, several organ and tissue samples were collected for gossypol analyses. In both experiments, the addition of (+)-gossypol to the diet reduced egg production. Only laying and broiler breeder hens fed (+)-gossypol produced eggs with severe yolk discoloration (score > or = 4). Total feed intake was lower (P < 0.05) in laying hens fed the 400 mg/kg level of (+)-gossypol compared with laying hens fed the other dietary treatments. In contrast, broiler breeder hens consumed less of the diet supplemented with (-)-gossypol. In both experiments, tissue accumulation of (+)-gossypol was higher than (-)-gossypol, with the exception of bile and excreta. The results suggest that in hens the ingestion of (+)-gossypol has a greater effect on egg yolk discoloration than the consumption of (-)-gossypol.

A comparison of methods to determine amino acid digestibility of feed ingredients for chickens.

Two experiments were conducted to compare standardized ileal amino acid (AA) digestibility in 7- and 21-d-old chicks and true AA digestibility as determined by the precision-fed cecectomized rooster assay for several ingredients used in poultry feeds. Diets were formulated to contain soybean meal, cottonseed meal, poultry by-product meal, and fish meal in experiment 1 and corn, wheat, soybean meal, poultry by-product meal, feather meal, and fish meal in experiment 2 as the sole sources of protein. Celite, used as an indigestible marker, was added at 1.5% of the diet. The test diets were fed ad libitum to broiler chicks from 0 to 7 d of age in experiment 1 and from 4 to 7 and 17 to 21 d of age in experiment 2. Ileal digesta samples were collected after euthanizing the birds at 7 d of age in experiment 1 and at 7 and 21 d of age in experiment 2. Additionally, cecectomized, Single-Comb White Leghorn roosters were used for crop intubation of the test diets for determination of true AA digestibility. In experiment 1, AA digestibility of all ingredients tested was significantly lower at 7 d of age than when determined by the rooster assay. In experiment 2, no differences were detected between AA digestibility at 7 or 21 d of age in the chick assay for the majority of the indispensable AA. However, the AA digestibility coefficients obtained by the chick assay at 7 d and, in some cases, at 21 d of age, were significantly lower than those obtained by the rooster assay. In conclusion, there were differences in the AA digestibility coefficients obtained through the chick and the rooster assays. Such discrepancies could be associated with an age effect or the methodological differences between both methods.

Levels of beta-mannan in soybean meal.

Beta-mannan, also known as beta-galactomannan, is found in a number of feed ingredients for poultry. Of these, soybean meal (SBM) is by far the most commonly used, being the primary source of protein in poultry feeds in most countries. Although beta-mannan has clearly been shown to be deleterious to poultry and animal performance, a survey of its concentration in SBM has yet to be reported. Thirty-six samples of SBM, identified as either dehulled or nondehulled, were obtained from commercial sources in a number of countries and assayed for beta-mannan content. Results confirmed that all samples of SBM assayed contained at least 1.0% beta-mannan and that concentrations are higher in nondehulled (1.61 +/- 0.20%) than in dehulled samples (1.26 +/- 0.14%).

Relative toxicity of gossypol enantiomers in broilers.

Use of cottonseed meal in poultry diets has been avoided in large part because of fear of gossypol toxicity. Gossypol exists naturally as a mixture of 2 enantiomers that exhibit different biological activities. Two experiments were conducted to determine the relative toxicity of gossypol enantiomers on broilers. In the first experiment, 3-d-old broilers were fed a standard diet containing 0, 100, 200, 300, or 400 mg of gossypol from gossypol acetic acid per kilogram of diet from 3 to 42 d of age. This form of gossypol contains both enantiomers in an equimolar ratio. Each dietary treatment consisted of 6 replicate pens of 4 birds. In the second experiment, 3-d-old broilers were divided into 15 pens of 4 birds each and fed a standard diet supplemented with either no gossypol or one of the gossypol enantiomers at 200 or 400 mg/kg of diet from 3 to 21 d of age. In both experiments, feed intake and BW gain were measured. In addition, several organ and tissue samples were collected at 21 d (experiments 1 and 2) and 42 d (experiment 1) of age and analyzed for gossypol. In experiment 1, feed consumption and BW gain were reduced (P < 0.05) at 21 and 42 d for the birds fed the highest level of gossypol. The concentration of gossypol in the heart, kidney, and plasma were equivalent at 21 and 42 d of age. In experiment 2, total feed consumption was reduced only in birds consuming (-)-gossypol, but BW gains were lower for birds fed either enantiomer. However, (-)-gossypol was more detrimental to growth than (+)-gossypol. The liver had the highest tissue concentration of both enantiomers, and accumulation of (+)-gossypol was higher than (-)-gossypol in all tissues examined. No racemization of the enantiomers was apparent in the tissues analyzed. Our results indicated that both gossypol enantiomers were toxic to broilers but that (-)-gossypol was more harmful to efficient broiler production than (+)-gossypol.

Evaluation of distillers dried grains with solubles as a feed ingredient for broilers.

Two experiments were conducted to evaluate the use of distillers dried grains with solubles (DDGS) from modern ethanol plants in broiler diets. Experiment 1 was a 2 x 2 factorial experiment with diets containing 2 levels of DDGS (0 and 15%) and 2 diet densities (high and low). The high- and low-density diets were formulated to contain 22% CP and 3,050 kcal MEn/kg and 20% CP and 3,000 kcal MEn/kg, respectively. Eight pens of 6 chicks were fed an experimental diet from 0 to 18 d of age. Weight gain and feed efficiency (gain:feed ratio) of the chicks receiving the high-density diets were (P < 0.05) better than those of chicks fed the low-density diets. However, within the 2 density levels there was no difference in performance of chicks fed diets with 0 or 15% DDGS. In experiment 2, 6 replications of 50 chicks were fed 1 of 4 dietary treatments for 42 d. The diets were formulated to be isocaloric and isonitrogenous and contained 0, 6, 12, or 18% DDGS. There was no significant difference in performance or carcass yield throughout the 42 d experiment except for a depression in BW gain and feed conversion when chicks were fed diets with 18% DDGS in the starter period. These studies indicate that DDGS from modern ethanol plants is an acceptable feed ingredient for broiler diets and can be safely used at 6% in the starter period and 12 to 15% in the grower and finisher periods.

The effect of dietary lysine deficiency on the immune response to Newcastle disease vaccination in chickens.

The effect of lysine deficiency on chicken immune function was evaluated using broiler chickens fed a diet with lysine at 67% of the control diet (1.24% lysine). The evaluation of humoral immune function was conducted by measuring the antibody production to a live Newcastle disease virus (NDV) vaccination using the hemagglutination inhibition (HI) test and enzyme-linked immunosorbent assay (ELISA). The cellular immune function was evaluated through the use of cutaneous basophil hypersensitivity test. The antibody response to NDV vaccination was reduced in broiler chickens fed a lysine-deficient diet when measured by ELISA but not when measured by HI. The cell-mediated immune response was also reduced by lysine deficiency.

Effect of dietary raw soybeans on coccidiosis in chickens.

Six battery experiments determined the effect of feeding raw soybeans (RSB) in corn-soybean diets on coccidiosis in broiler chickens. The experimental design represents a 2 x 3 factorial arrangement of treatments with three dietary levels of incorporation of RSB (0, 50, and 100%), and chickens either infected or uninfected. The coccidial species tested singularly were Eimeria acervulina, Eimeria maxima, Eimeria necatrix, Eimeria brunetti, and Eimeria tenella. With all species of Eimeria a significant diet by infection interaction was demonstrated with a stepwise increase in weight gain and reduction in lesion scores with increasing levels of raw soybeans. To cause the pancreas to become hypertrophied and hyperfunctional, the 100% RSB diet was fed for an extended period. The experimental design represents a 2 x 3 factorial arrangement of treatments with three feeding regimens [Treatment A: 0% RSB (0 d to termination), Treatment B: (0% RSB: 0 to 12 d then 100% RSB 12 d to termination), and Treatment C: (100% 0 d to termination)] and chickens either infected (E. tenella) or uninfected. There was a significant difference for weight gain between uninfected and infected chicks of Treatments A and C but this difference was absent for Treatment B. Coccidiosis was not reduced by continuously feeding 100% RSB (Treatment C).

Critique of methods of estimating the variability of metabolizable energy from assays with fasted roosters.

Metabolizable energy values from assays with fasted roosters are often calculated: 1) without regard to variability in data from control roosters, 2) with chemical determination on pooled and not individual data, and 3) from data sets with statistically aberrant points removed. Data from determinations of the ME of a feather meal sample were used to examine the influence of these practices on the reported mean and variance values. Ignoring the variability of the fasted controls or pooling excreta samples did not have large effects on the means or variances of these samples. Eliminating data from roosters whose excreta weights are more than one standard deviation from the mean had little effect on the mean value but made the variance appear much smaller than it actually was. As a result of these practices, researchers may place too much confidence in their data and fail to use enough replicates (roosters) to justify that confidence.

Nutritive value of poultry by-product meal. 1. Metabolizable energy values as influenced by method of determination and level of substitution.

Experiments were conducted to determine the metabolizable energy (MEn) of eight poultry by-product meal (PBPM) samples. Samples averaged 5.44% moisture, 4.84 kcal gross energy (GE)/g dry matter (DM), 61.2% crude protein, 13.38% ether extract, 16.1% ash, 5.14% calcium, and 2.36% phosphorus. Samples of PBPM were substituted in the diet at levels of 20 and 40%. Values of ME were calculated with substitution for the diet (Matterson's method) and for glucose (Hill's method) and by the fasted cockerel method. Values of PBPM MEn were 7.9% greater when substitution was for diet as compared with substitution for glucose; values were 2.95 and 2.74 kcal/g DM, respectively. Using Matterson's method with three samples, MEn values were determined to be 12.1% greater when PBPM was substituted at the rate of 20% than at 40%; values were 3.33 and 2.97 kcal/g DM, respectively. Differences in MEn between the best and poorest samples (3.79 and 2.77 kcal/g DM) could be attributed to differences in gross energy (5.00 and 4.49 kcal/g DM) and percentage of gross energy metabolized (75.7 and 61.7%). Metabolizable energy was more closely related to body weight gains than the amount of feed consumed. When a modification of Sibbald's fasted cockerel technique was used, true MEn of the eight samples averaged 3.35 kcal/g DM and 69% of GE metabolized. For the three samples assayed by both methods, Matterson's method gave values averaging .97% higher than Sibbald's (+4.3, +.8, and -2.2%). Differences in MEn were mostly highly correlated with ash (-.89), calcium (-.85), and GE (.78) contents of the diets. Projections from relationships found between ME and nutrient compositions of these samples to the average sample used by the poultry industry in the Southeast indicate an average of 3.57 kcal ME/g DM of PBPM (3.39 kcal/g as is).

Comparison of heat production of chickens measured by energy balance and by gaseous exchange.

An open-circuit respiration calorimeter suitable for chickens or other small animals has been constructed. The system contains two animal chambers and is capable of determining heat production of two animals or groups of animals independently and simultaneously with gas collection apparatus for continuous sampling of chamber gases. The operation of the system was tested in two experiments by determining heat production of two groups of 10-week-old, full-fed cockerels over a 4-day period both by energy retention (body balance) and gaseous exchange. Heat production (kilocalories per bird per 24 hours) as determined by energy balance versus gaseous exchange was 359 versus 348 in one experiment and 395 versus 393 in the other. The agreement was sufficiently close to support the use of respiration calorimetry to measure heat production of chickens under experimental conditions in this laboratory without killing the experimental subjects. On the basis of metabolic body weight (in kilograms, W0.75) heat production measured in this manner was 161 and 173 kcal (day . W0.75) in experiments 1 and 2, respectively.

True metabolizable energy of fats at low level dietary inclusion.

When assayed at a 2.5% level of inclusion in a corn-soybean meal basal diet with 40 replications per treatment, no significant differences could be demonstrated between the true metabolizable energies (TME) of corn oil and two samples of tallow varying in stearic acid (18:0) content. All values were in excess of the gross energy of fat, suggesting an improvement in the absorption of other dietary constituents. When assayed at a 15% level in a purified basal diet, the TME of corn oil was significantly higher than that of the tallows; all values were below the gross energy of fat. Use of the practical corn-soybean meal basal improved the TME of the fats by 22.4% (corn oil), 34.9% (low 18:0 tallow), and 43.0% (high 18:0 tallow). A portion of the improvement in the TME of the tallows is presumed to be accounted for by an interaction with fatty acids in the practical basal ingredients that may be obscured at higher levels of inclusion. It is concluded that with adequate replication it is feasible to assay the TME of fats at low levels of dietary inclusion. A comparison of fatty acid absorption in Single Comb White Leghorn roosters during a TME study and in 8 to 9 week broilers on a full-feed regimen suggests that the conditions imposed during a TME assay provide a satisfactory model for evaluating the fat absorption of chickens reared under normal conditions.

Additive toxicity of aflatoxin and dietary tannins in broiler chicks.

In two experiments graded levels of either aflatoxin and tannic acid (experiment 1) or aflatoxin and a high-tannin variety of grain sorghum (BR-64) (experiment 2) were incorporated into broiler chick starting diets in a factorial design. When present singly, aflatoxin and both tannic acid and high tannin sorghum significantly depressed chick growth. When present in combination, and deleterious effects of aflatoxin and either tannic acid or high tannin sorghum on chick growth and feed conversion ratios were found to be additive.

Additivity of true metabolizable energy values as measured with roosters, broiler chicks and poults.

True metabolizable energy (TME) values were determined for five feed ingredients (yellow corn, dehulled soybean meal, corn gluten meal, menhaden fish meal, and poultry byproduct meal), and three combinations of these ingredients, using Single Comb White Leghorn roosters, 6-week-old broiler males (Cobb), and 6-week-old male turkey poults (Large White). There was generally good agreement in th TME values between roosters, broilers, and poults although the values for broilers tended to be slightly lower than for roosters or poults. Values for the ingredient combinations as assayed with the three classes of birds showed differences of 3% or less between "predicted" and "determined" in seven of nine comparisons, indicating a satisfactory degree of additivity of TME values for these ingredients.

Effect of diet composition on feed intake and growth of chicks under heat stress. II. Constant vs. cycling temperatures.

Broiler chicks 5 to 7 weeks of age were subjected to a constant cool (14 +/- 1 C) or hot (31 +/- 1 tc) environment and fed diets varying in fat level and energy and nutrient density. Chicks gained significantly (P less than or equal to .01) more body weight in the cool than in the hot environment. In both environments chicks fed high fat or high fat-high density diets gained more weight than those fed diets low in fat, and there was no diet X temperature interaction. When temperatures were cycled diurnally (cool, 14 to 22 C; hot, 22 to 33 C), as would occur under natural conditions, the growth depression due to heat stress was less in chicks fed the diets high in fat. The special benefit of fat at high temperature was probably the result of reduced heat increment. Under constant temperature conditions, chicks in the cool environment, pair-fed at the same level of feed intake as those in the hot environment, gained significantly (P less than or equal to .05) more weight than the latter. These data indicated that factors other than reduced feed intake contributed to the growth depression associated with high temperature. Thyroid size was significantly (P less than or equal to .05) reduced in chicks held at constant high temperature and slightly but not significantly reduced in chicks subjected to cyclic heat stress. This decrease in thyroid size suggested there is a practical limit on overcoming by nutritional means the deleterious effects of heat stress in broilers.