Nutritional evaluation of low glucosinolate mustard meals (Brassica juncea) in broiler diets

Experiments were conducted to evaluate the nutritional value of meal derived from low glucosinolate cultivars of mustard (Brassica juncea) in comparison to samples of canola meal (Brassica napus, Brassica rapa). Samples of Brassica seed (four B. juncea, one B. napus, and one B. rapa) were processed using laboratory procedures to produce oil-extracted meals, which were examined for composition (DM basis), and nutritional value for broiler chickens as judged by nutrient retention (AMEn, ileal protein digestibility) and performance. Meals derived from B. juncea contained more CP and less total dietary fiber (TDF) on a dry basis than either B. napus or B. rapa, 45.9 vs 44.6 and 43.1% CP and 27.22 vs 29.47 and 29.67% TDF, respectively. Acid detergent fiber (ADF) and neutral detergent fiber (NDF) levels for B. juncea and B. rapa meals were similar to each other, but lower than those of B. napus, 12.79 and 13.20 vs 20.6% ADF, and 21.15 and 19.58 vs 29.47% NDF, respectively. Brassica juncea meals contained more glucosinolates than B. napus and B. rapa, 34.3 vs 21.8 and 25.5 mumol/g total glucosinolates, respectively. Brassica juncea meals were equal or superior to B. napus and B. rapa meals for AMEn and apparent ileal protein digestibility. Similarly, broilers fed B. juncea meals grew as quickly and converted feed to BW gain as efficiently to 21 d of age as those birds fed B. napus and B. rapa meals. Feeding meal from B. rapa reduced growth rate and gain to feed ratio. In conclusion, the nutritional value of meal from low glucosinolate mustard was equal or superior to that of canola meal samples derived from B. napus and B. rapa cultivars.

Malignant ventricular dysrhythmia in broiler chickens dying of sudden death syndrome

A flock of broiler chickens was monitored intensively for overt signs indicative of sudden death. Electrocardiographic tracing of terminal cardiac activity was obtained from six broilers succumbing to sudden death syndrome and from six control chickens which were killed by cervical dislocation. Normal sinus rhythm, heart rate and electrocardiogram (ECG) pattern with P, QRS, and T deflections were observed for two to three minutes in the control chickens. The ECG tracing from birds dying of sudden death syndrome showed no identifiable P, QRS, or T waveforms. Initial more regular oscillatory waves resembling ventricular flutter, changed to irregular, undulating waves characteristic of ventricular fibrillation. A straight line, indicating cessation of heart activity, appeared within four to six minutes of the onset of clinical signs. It was concluded that the sudden death syndrome is associated with an acute cardiovascular failure caused by a lethal cardiac dysrhythmia, ventricular fibrillation.

A study of electrocardiographic patterns in a population of commercial broiler chickens

A study was completed to characterize the electrocardiographic (ECG) patterns of male broiler chickens. Data were collected from 300 commercial broilers. ECG readings were collected from all birds between 12 and 15 days of age and then twice more at 10-day intervals. The measurements. included heart rate and rhythm, QRS complex duration, amplitude and mean electrical axis (MEA), incidence of ascites and incidence of sudden death syndrome (SDS). Eight birds died from SDS and 4 birds died from ascites. Twelve birds were condemned for ascites at the processing plant. The overall population heart rate declined with age. Birds that died of SDS had a higher heart rate, whereas those that developed ascites had a lower heart rate than the remainder of the population. The normal MEA was found to be between 0 degree and 180 degrees. On average 30% of birds showed left or right QRS axis deviation, and this pattern was observed in 14 of the 16 birds that developed ascites. Several types of cardiac arrhythmias were observed, the most common being premature ventricular contractions (PVC). The incidence of PVC increased with age, ranging from 1% at 12-15 days of age to 8.9% at 32-35 days of age. QRS axis deviation was present in 5 SDS birds. It is concluded that some 30% of the broiler flock tested was at risk of developing heart failure or heart-related disease.

Changing epidemiology of ascites in broiler chickens

Ascites has become a major economic problem in modern broiler operations world wide. Estimated losses to the global economy likely amount to hundreds of millions of dollars annually, however, accurate statistics are not available. Epidemiological information on incidence of ascites is scanty. The present work examines the condemnation records between 1986 and 1994 from federally inspected slaughtering plants in Canada. The analysis reveals that there has been a steady increase in ascites condemnation during this period. National average figures showed a nearly sixfold increase in condemnations due to ascites from 1986 to 1994. It is estimated that in Canada some 6–8 million chickens developed ascites in 1994. The present data have shown an alarming trend in the epidemiology of ascites. Key words: Chicken, broiler, ascites, condemnation, epidemiology

Live performance and health of broiler chickens fed diets diluted with whole or crumbled wheat

Broiler chicken diets were diluted with three levels of whole wheat and two levels of crumbled wheat to determine how feeding whole grain and diluting feed with wheat would alter the performance of male and female broilers. Grit was not used. The amount of extra wheat added increased from 5% at 11 d of age to a maximum level of 30% at 31 d of age. Body weight at 41 d of age averaged 2.130 kg for pullets and 2.422 kg for cockerels and was unaffected by diluting with wheat, in whole or crumbled form. Total mortality and cause of mortality were similarly unaffected by dilution and form of wheat. The feed:gain ratio from 11 to 41 d of age was increased significantly for cockerels from 1.75 at zero dilution to 1.84 at maximum dilution. Dilution did not affect the feed conversion of pullets and form did not influence the feed conversion of either sex. Dilution of broiler rations may be profitable because of the limited effect on bird performance. Pelleting all the wheat in poultry rations is unnecessary because bird performance is unaffected by feeding up to 30% whole grain in the finisher diets. Key words: Broiler chickens, whole wheat, pelleting

The effects of continuously or diurnally fed melatonin on broiler performance and health

An experiment was designed to investigate the effects of dietary melatonin (MEL) on the performance and health of broiler chicks. Chicks raised under constant lighting were fed practical broiler diets in mash form containing 0, 20, or 40 ppm MEL from 0 to 3 wk. A fourth treatment (0 ppm MEL: 6h/d; 20 ppm MEL: 18 h/d) was used to mimic a diurnal light:dark cycle. Commercial broiler grower diets without MEL supplementation were fed from 3 to 6 wk of age. A small dose-related decrease was observed in weight gain (0 to 14 d) and feed consumption (0 to 21 d) due to continuous feeding of MEL. Continuously fed MEL also improved feed efficiency in the first 3 wk vs the control (0 ppm). Growth and feed consumption from 0 to 21 d were not affected by the diurnally fed diet when compared with the control treatment. No effects were found for mortality. However, the incidence of sudden death syndrome (SDS) was numerically less for the diurnal (3.56%) and 40 ppm (3.76%) diets from 0 to 42 d than for the control treatment 5.56%. Skeletal disease was generally unaffected, with the exception of the incidence of crooked toes at 42 d (0 ppm MEL: 8.67% vs diurnal: 4.89%). Dietary MEL fed either continuously or in a diurnal pattern had a minor effect on the performance and health of broiler chickens.

Removal of the alpha-galactosides of sucrose from soybean meal using either ethanol extraction or exogenous alpha-galactosidase and broiler performance

Two studies using broiler chicks and one using adult White Leghorn roosters were conducted to determine the influence of stachyose and raffinose (alpha-galactosides of sucrose) present in soybean meal (SBM) on the nutritional value of the meal. In Experiment 1, the addition of four levels (0, .05, .10, or .20 g/kg) of alpha-galactosidase with and without 1 g/kg of invertase to a corn-SBM diet had no effect on weight gain, feed efficiency, protein digestibility, or the digestible energy value of the feed when fed to broiler chicks. However, both enzymes decreased (P < .001) dietary AMEn. In Experiment 2, ethanol extraction and incubation of SBM with alpha-galactosidase decreased the concentrations of the alpha-galactosides of sucrose in SBM from 6.59 to .81 and 1.43%, respectively. However, when broiler chicks were fed semi-purified diets containing SBM, ethanol-extracted SBM, water-incubated SBM, or water plus alpha-galactosidase-incubated SBM, no improvements in weight gain, feed efficiency, or apparent protein digestibility were observed. There was also no improvement in TMEn when the above meals were precision fed to adult White Leghorn roosters (Experiment 3). These results indicate that the removal of up to approximately 90% of the alpha-galactosides of sucrose has no beneficial effect on the nutritional value of SBM for chickens.

Effect of lighting treatment on the productivity, health, behavior and sexual maturity of heavy male turkeys

1. Turkey poults (1620) were used to compare the effects of three lighting programmes on heavy strain males reared to 188 d: constant light (24L:0D, CON); increasing light (6L:18D at 7 d gradually increasing to 20L:4D by 63 d, INC); a pattern identical to INC followed by a decrease in daylength from 84 d to 10L:14D at 112 d (DID). 2. Lighting affected growth pattern but had no effect on body weight at 118 d or overall food to gain ratio. 3. Both INC and DID lighting reduced overall mortality in comparison to CON light primarily because of a reduction in the incidence of skeletal disease and spontaneous cardiomyopathy. INC and DID lighting increased the incidence of cannibalism. 4. Turkeys given INC or DID lighting had a superior ability to walk in comparison to those birds given CON light. 5. INC and DID males stood, ate and drank more frequently, and sat less often than CON turkeys during behavioural observation. 6. There were no lighting effects on carcase composition except that INC and DID birds had heavier keel bones. The ultimate force per cm2 (stress) required to break femora was greater for turkeys given INC and DID lighting (P = 0.065). 7. Plasma testosterone concentrations at 117 d were 272.5, 115.2 and 29.5 pg/ml for turkeys given CON, INC and DID lighting, respectively (P = 0.072). Testosterone concentration was not related to growth rate.

An in vitro assay for prediction of broiler intestinal viscosity and growth when fed rye-based diets in the presence of exogenous enzymes

A two-stage in vitro assay procedure was developed for predicting the efficacy of microbial enzyme sources in rye-based diets for broiler chicks. The procedure uses the complete diet as substrate to predict the in vivo intestinal viscosity and final weight of birds fed such diets. The optimum conditions for maximizing in vitro viscosity of a rye-based diet consisted of digesting .6 g of diet (ground through a 1-mm screen) in .9 mL of .1 N HCl containing 2,000 U pepsin/mL for 45 min at 40 C. At the end of this incubation phase, .3 mL 1 M NaHCO3 containing 8 mg pancreatin/mL (8 x USP) was added and the tube sealed and incubated for 2 h with intermittent vortexing. The digesta was then centrifuged (12,700 x g) and the supernatant collected for viscosity analysis using a digital viscometer. This assay was used for a rye-based diet containing either 0, .1, .2, .4, .8, or 1.6% of a xylanase source (experimental Trichoderma longibrachiatum product). The results were compared to weight and intestinal viscosity proximal and distal to Meckel's diverticulum of broilers (19 days of age) that had been fed these diets. The in vitro assay accurately predicted the in vivo intestinal viscosity (proximal r2 = .758, P < .0001, distal r2 = .667, P < .0001) and final weight of these birds (r2 = .660, P < .0001). The data suggest that the in vitro assay is a reliable assay for assessing the growth-promoting ability of an enzyme preparation in chicks fed rye-based diets.

Growth, body composition, and plasma androgen concentration of male broiler chickens subjected to different regimens of photoperiod and light intensity

Day-old male Hubbard broilers (960) were assigned to one of four treatments (two pens of 120 birds per treatment) to evaluate the effects of high (150 lx) versus low (5 lx) light intensity and constant 23 h light (L):1 h dark (D) versus increasing (6L:18D increasing 4 h/wk to 23L:1D) photoperiod in a 2 x 2 factorial arrangement of treatments. Birds were raised to 8 wk on a typical commercial four-diet program. Low-intensity birds were heavier than high-intensity birds from 2 to 8 wk (3.25% heavier at 8 wk). Birds raised under constant photoperiod were heavier than birds raised under increasing photoperiod from 2 to 5 wk and at 7 wk of age (1.71% heavier at 7 wk). High-intensity bird carcasses had lower percentage body fat, weight of fat, and higher percentage body protein at 8 wk compared with low-intensity bird carcasses (7.77, 10.76, and 1.77%, respectively). High-intensity birds had smaller abdominal fat pads (weight and percentage of body weight) at 8 wk compared with low-intensity birds (15.46 and 12.17%, respectively). Photoperiod did not affect body composition. Birds treated with increasing photoperiod had larger testes (weight and percentage of body weight) at 8 wk compared with birds under the constant photoperiod (29.36 and 30.51%, respectively). Birds treated under increasing photoperiod had higher plasma androgen concentrations at 7 wk compared with birds under constant photoperiod (testosterone, .270 versus .188 ng/mL; androstenedione, .632 versus .494 ng/mL).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of increasing photoperiod length and anticoccidials on performance and health of roaster chickens

Male broiler chickens were raised to 63 days of age under different lighting and anticoccidial treatments. A constant-light program was compared with two interrupted and increasing-light programs in which the photoperiod length was 6 hours between 7 and 14 days of age and then increased gradually to continual light by 49 days of age in the first program and more gradually to 18 hours by 49 days of age in the second program. By 63 days of age, the increasing-light programs significantly increased body-weight gain and decreased feed/grain ratio, but not significantly. The increasing-light programs reduced the incidence of skeletal disease from 7.56% to 2.88% in the first program and to 3.53% in the second program, reduced the incidence of acute death syndrome from 5.94% to 3.37% in the first program and to 4.65% in the second program, and reduced total mortality from 18.81% to 11.71% in the first program and to 11.38% in the second program. The lighting programs had no effect on the incidence of ascites and right heart failure, the ratio of right ventricular weight to total ventricular weight, the incidence of clinical and subclinical tibial dyschondroplasia, and the number of cartilaginous and osseous nodules in the lungs. The anticoccidials compared were monensin and amprolium/ethopabate, from 0 to 35 days of age. These treatments had no significant direct effects on any of the parameters measured.

Induction of immunity to spermatozoa in male domestic fowl and effects on fertility

Male fowl were immunized intravenously (i.v.) or intramuscularly (i.m.) with spermatozoa to assess the effects of immunity to spermatozoa on fertility. Histological and immunofluorescence evaluations of testis and ductus deferens tissues after 24 weeks of immunizations revealed immune cell infiltration and immunoglobulin associated with spermatozoa. The long-term immunization regimen resulted in significant antisperm antibody titres in the immunized groups. When semen from i.v.-immunized males was used to inseminate females, fertility over 7 days was reduced (P less than 0.05). A subsequent experiment using a 10-week i.v. immunization scheme also led to high antisperm titres. Spermatozoa from these males were characterized by lower fertility and duration of fertility than those of controls (P less than 0.05). As in mammals, a reduction in fertility may result from exposure of avian males to sperm antigens.

The effect of dietary enzyme supplementation of rye- and barley-based diets on digestion and subsequent performance in weanling pigs

Two experiments were conducted to determine the effect of xylanase (850 U g−1) supplementation of a rye and soybean meal-based diet (exp. 1) and β-glucanase (1086 U g−1) supplementation of a barley- and soybean-meal-based diet (exp. 2) on the progress of protein and starch digestion throughout the small intestine. In each experiment, 12 weanling pigs per treatment were fed the experimental diet for a 10-d period, at the end of which feed intake and weight gain were recorded and samples of digesta were collected from the small intestine, colon and rectum. Xylanase supplementation did not result in any improvement in rate or efficiency of gain, feed intake, starch or protein digestibility (P > 0.05). Digesta viscosity was increased by enzyme supplementation in some sections of the small intestine. β-glucanase supplementation resulted in a significant (P < 0.05) increase in rate of gain and improved protein digestibility in the colon and in the last three-quarters of the small intestine, but had no effect on starch digestibility. In conclusion, β-glucanase supplementation of barley/SBM-based diets for young weanling pigs was of benefit whereas pentosanase supplementation of rye/SBM-based diets was not. Key words: Swine, pentosanase, β-glucanase, digestion, barley, rye

Reduction of intestinal viscosity through manipulation of dietary rye and pentosanase concentration is effected through changes in the carbohydrate composition of the intestinal aqueous phase and results in improved growth rate and food conversion efficiency of broiler chicks

The effect of dietary rye (0, 200, 400 and 600 g/kg substituting for wheat) and pentosanase concentration (0, 1, 2, 4, 8, 16 g/kg) on weight gain, molecular weight distribution of soluble carbohydrates in the intestinal lumen and lumenal viscosity in broiler chicks was investigated. A 4 x 6 factorial design was used with four replicates per treatment and six birds per replicate pen. Diets were fed from 1 to 19 d of age, at which time body weight, food intake and intestinal viscosity and molecular weight distribution of carbohydrate complexes in proximal and distal gut sections were determined. Weight gain and food conversion efficiency (FCE) improved with increasing pentosanase and decreasing rye concentration. Intestinal viscosity, which rose as digesta passed from the proximal to distal small intestine, fell with pentosanase addition and decreasing rye concentration. Intestinal viscosity, which correlated positively with reduced weight gain and FCE, was in turn correlated with the lumenal concentration of soluble high-molecular-weight carbohydrates (HMC, greater than 500 kDa), which constituted less than 15% of the total lumenal carbohydrate concentration. The arabinose and xylose content of the HMC increased with increasing rye concentration, suggesting that HMC composition in addition to concentration may determine intestinal viscosity. The results indicate that pentosanase isolated from rye by extraction methods may not be representative of those released by digestion.

Genotypic and environmental differences in rye fed to broiler chicks with dietary pentosanase supplementation

The response of broiler chicks fed rye with dietary pentosanase supplementation was examined with respect to rye variety, area of production, and maturity at harvest. There were significant differences among varieties in the absence of enzyme addition and significant differences (variety × enzyme, P < 0.01) in the magnitude of the chick growth response to dietary pentosanase (exp. 1). Kodiak and Cougar rye gave greater enzyme-induced growth response than did Gazelle rye, with Musketeer rye and an unknown sample displaying intermediate values. Experiment 2 gave similar results; both Kodiak and Cougar rye in chick diets gave a larger response to dietary pentosanase than did Musketeer rye (P > 0.05). Determination of soluble carbohydrates, as well as extract viscosity, indicated that Kodiak rye had higher extract viscosity, higher extractable pentosan content, and a lower arabinose-to-xylose ratio; however, these results were not consistent with Cougar rye. Differing production location of a single variety (Musketeer, exp. 3) or maturity at harvest (exp. 4) indicated no significant effect on the nutritive value of rye attributable to location or maturity with or without enzyme supplementation, nor was there an effect on the magnitude of enzyme response. In rye harvested at different stages of maturity there was, however, a nonsignificant linear depression in chick growth with rye harvested at higher moisture levels. Key words: Rye, pentosans, broiler chicks, pentosanase

The effect of pelleting, salt, and pentosanase on the viscosity of intestinal contents and the performance of broilers fed rye

An experiment was conducted to determine the impact of pelleting of rye, dietary salt (.39 and .57%), and crude pentosanase supplementation (0 and .2%) on the viscosity of intestinal contents and the concomitant performance of broiler chicks fed rye-based diets. Each treatment was replicated six times with six birds per replicate. Test diets were fed from 1 day to 3 wk of age, at which time body weight, feed intake, intestinal viscosity, and molecular weight distribution of carbohydrate complexes were determined in fore and hind gut sections. Enzyme supplementation in all treatment combinations significantly increased weight gains and feed conversion efficiency (FCE). Pelleting and salt did not influence weight gain or FCE, although feed intake was increased through the addition of salt. The viscosity of fore and hind gut contents was significantly reduced with pentosanase supplementation, whereas the effects of salt or pelleting were not as clearly defined. Weight gain and FCE correlated with fore but not hind gut viscosity. The viscosity of gut samples was found to be best described by the concentration of carbohydrate complexes with an average molecular weight greater than 500,000 Da. Pentosanase treatment reduced lumenal concentration of these complexes, thereby reducing viscosity and stimulating improvements in growth and FCE.

Heat pretreatment as a means of improving the response to dietary pentosanase in chicks fed rye

Three experiments were conducted to study the effect of heat and acid treatment of rye and wheat on the response of broiler chicks to dietary pentosanase. In exp. 1, autoclaving rye greatly potentiated the growth response to dietary pentosanase (P < 0.01) while producing little or no effect without enzyme. Acid treatment (0.2 N HCl) alone, or in conjunction with autoclaving, improved the performance of broilers fed rye but did not enhance the enzyme response. Examination of the pentosan content or viscosity of treated rye indicated no substantial effect of autoclaving, although some breakdown of pentosan was apparent in the presence of acid. A second experiment confirmed the enzyme potentiating effect of autoclaving in broilers fed rye (cv. Musketeer and Kodiak) and wheat. The response to dietary enzyme was greater for rye than wheat. Viscosity determinations of intestinal contents indicated that autoclaving enabled the dietary pentosanase to reduce viscosity to a greater extent than that achievable with enzyme alone. In exp. 3, Musketeer rye subjected to commercial heat-processing procedures gave a similar response to that observed with autoclaving, although differences in effectiveness were seen. Pelleting alone (without enzyme supplementation) resulted in improved weight gain and feed conversion of chicks fed rye. Both pelleting and micronizing, but not steam-flaking, resulted in a greater response (P < 0.10) to dietary pentosanase. Key words: Broiler chicks, rye, pentosanase, heat treatment

Effects of increasing photoperiod length on performance and health of broiler chickens

1. Broiler performance and health were compared from 0 to 42 d for lighting programmes consisting of near-continuous light 23L:1D (23L), a lighting programme where photoperiod gradually increased from 6 to 23 h between days 4 and 35 (INC) or an increasing-lighting programme with 1 h of light mid-way through the scotophase (INC + 1). 2. The increasing lighting programmes reduced growth rate and increased gain:food ratio from 0 to 21 d; INC + 1 growth rate was intermediate to the 23 L and INC treatments. From 0 to 42 d there were no differences in growth rate or gain:food ratio among lighting treatments. Males grew faster, ate more food and converted food more efficiently than females. 3. The increasing-lighting programmes (INC and INC + 1) resulted in less skeletal disease than the 23L control. The incidence of sudden death syndrome (SDS) and mortality other than SDS were numerically lower for the increasing lighting treatments. More males died as a result of SDS and were affected by skeletal defects than females. 4. In terms of health, increasing lighting programmes were superior to near-continuous light for broiler chickens.

Photoperiodic effects on performance and leg abnormalities in broiler chickens

Three experiments were conducted to examine the impact of changing photoperiod length on the performance of chicken broilers. Effect of long, constant (23-h) photoperiod length (23H) was compared with treatments where photoperiod increased from 6 to 23 h abruptly after 21 days (6H) or gradually during the experiment (INC). The 6H program was used in all three experiments, whereas the INC treatment was included only in Experiment 3. Differences between total body weight gains of birds in the 6H and 23H treatments were inconsistent and small in the three experiments. In Experiment 3, there were no differences between total body weight gains for INC, 6H, and 23H treatments. Feed-to-gain ratios for 6H broilers were significantly superior to those for birds on the 23H treatment for Days 0 to 21 (all experiments), Days 21 to 42 and Days 0 to 42 (Experiment 2), and inferior for Days 21 to 42 (Experiment 3). The INC treatment was significantly superior to the 23H program for all time periods and to 6H birds for Days 21 to 42 and Days 0 to 42. The 6H treatment significantly reduced the incidence of leg abnormalities in comparison with the 23H program in all experiments; the INC and 6H treatments were equal in incidence in Experiment 3. When data from the three experiments were combined, mortality due to sudden death syndrome and other causes for the 6H treatment was significantly lower than that of the 23H program; values for the 6H and INC treatments were not different in Experiment 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Prediction of metabolizable energy of broiler diets from chemical analysis

Eighty-six broiler diets were studied to develop prediction equations for true metabolizable energy (TME) with nitrogen correction (TMEn) and calculated apparent metabolizable energy (AMEn) from chemical composition. Analyses were selected according to their capacity to represent the terms used in energy calculations, namely, dietary gross energy and energy excreted relative to diet consumed. Dietary gross energy was found to be highly correlated with ether extract alone. Prediction of excreta loss improved substantially with inclusion of two terms: a measurement of fiber [either crude fiber (CF), acid detergent fiber (ADF), or neutral detergent fiber (NDF)] and ash. A composite variable based on starch plus crude protein in place of fiber and ash yielded similar predictions. Accuracy of prediction of TMEn approached that of the biological analysis, but prediction of TME was somewhat less successful. Neutral detergent fiber was less satisfactory as a predictor than ADF or CF. Calculated AMEn was also highly predictable from ether extract or diet gross energy and a measurement of fiber alone; ash apparently was less helpful for AMEn. Previously published equations based on ether extract, ash, and an estimate of fiber gave results similar to the derived equations.

Gamma irradiation treatment of cereal grains for chick diets

Wheat (W), triticale (T), hulled barley (HB), hull-less barley (HLB), hulled oats (HO), and hull-less oats (HLO) were gamma irradiated (60Co) at 0, 3, 6 and 9 Mrad to study the effect of irradiation on the nutritional value of cereal grains for chicks. A significant curvilinear relationship between radiation dose and 3-wk body weight of chicks fed irradiated cereals was noted for T, HB, HLB, HO and HLO. Chicks fed W or T showed no effect or lower body weight, respectively, while body weights of chicks fed barley or oat samples were higher with irradiation. The improvement tended to be maximal at the 6 Mrad level. Irradiation significantly improved the gain-to-feed ratio for chicks fed either HO or HLO. Apparent fat retention and tibia ash were higher in chicks fed irradiated HLO than in those fed untreated HLO. In a second experiment chick body weight, apparent amino acid and fat retention, tibia ash, and gain-to-feed ratios were lower in chicks fed autoclaved (121 degrees C for 20 min) barley than in those fed untreated barley. Irradiation (6 Mrad) subsequent to autoclaving barley samples eliminated these effects. Irradiation appears to benefit cereals containing soluble or mucilagenous fiber types as typified by beta-glucan of barley and oats. These fibers appear prone to irradiation-induced depolymerization, as suggested by increased beta-glucan solubility and reduced extract viscosity for irradiated barley and oat samples.

Effect of watering systems for floor-reared pullets on subsequent caged laying hen performance

Two watering system trials were conducted with floor-reared pullets. Trial 1 showed that pullets raised on trigger cups (STC) compared to pullets raised on dome waterers (DW) had significantly better feed conversion and lower mortality. A significant difference was shown between 4 and 5 hens per cage for hen-day egg production and feed per dozen eggs. There were no differences in production responses according to cage waterer availability or for main effect interactions. Trial 2 showed that raising pullets on STC, DW, or a DW to STC change during the rearing phase had no effect on cage laying performance. Mortality trends were shown according to waterer system. Trial differences were hypothesized to be associated with the laying cage waterer type used in each trial; fount cups were used in Trial 1 and TC in Trial 2.

Effect of fat retention on the rachitogenic effect of rye fed to broiler chicks

Two experiments were conducted to determine the influence of fat retention on bone mineralization and amino acid retention for broiler chicks fed rye diets containing marginal levels of vitamin D3. In Experiment 1, rye diets containing tallow were supplemented with high vitamin D3, bile salt (sodium taurocholate), or a detergent (sodium lauryl sulphate). Fat retention and tibia ash were improved (P less than .05) with bile salt addition, and tibia ash alone (P less than .05) was improved when high vitamin D3 or the detergent was added to the diet. In Experiment 2, rye diets contained tricaprylin (TC), tristearin (TS), or triolein (TO) as a fat source. Both fat retention (TS less than TO less than TC) and tibia ash (TS less than TC less than TO) showed a significant (P less than .05) treatment effect. The results of both experiments support the hypothesis that the rachitogenic effect of feeding rye may be related to inadequate fat digestion. There was no significant treatment effect on amino acid retention in either experiment. A third experiment indicated a similar bile acid pool size for chicks fed rye as opposed to wheat; however, bile acid concentration of jejunal fluid was lower (P less than .05) for chicks fed rye. A possible microbial involvement in the disturbance of bile acid metabolism was indicated by the capacity of Streptococcus organisms derived from chick small bowel to degrade sodium taurocholate.