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PubMed2003

Presence of Campylobacter inthe respiratory tract of broiler carcasses before and after commercial scalding.

Campylobacter could be detected in the thoraco-abdominal cavity of broiler carcasses even if they were carefully eviscerated by hand with no evidence of intestinal rupture or leakage. If Campylobacter is present in the air sacs, which are unavoidably torn during evisceration, it could contaminate the thoraco-abdominal cavity of the eviscerated carcass. This study was done to determine if Campylobacter contamination is present in the respiratory tract of broilers prior to evisceration. Whole carcass rinses and respiratory tract washes were done on broiler carcasses collected at a commercial processing plant just before and just after scalding. Samples were cultured for presence and numbers of Campylobacter, Escherichia coli, coliforms, and total aerobic bacteria. Campylobacter isolates were subtyped by sequencing the short variable region of the flaA gene. The same subtypes of Campylobacter were detected in whole carcass rinse samples as in respiratory tract wash samples from individual broilers. Furthermore, the same numbers and subtypes of Campylobacter were recovered from respiratory tracts of carcasses collected before scalding and those collected after scalding. However, respiratory tracts of carcasses after scalding had higher numbers of E. coli, coliforms, and total aerobic bacteria than those tested before scalding. Although some bacterial counts were higher in the respiratory tracts of carcasses after scalding, Campylobacter counts were not. It appears that Campylobacter is present in the respiratory tracts of broilers as they enter processing, and contamination may be due to airborne bacteria during production or transport.

Animals↗

PubMed2003

Effects of Chinese herbal polysaccharides on the immunity and growth performance of young broilers.

Two trials were conducted to study the effects of two Chinese herbal polysaccharides [achyranthan (ACH), a low-molecular-weight polysaccharide, and astragalan (APS), a high-molecular-weight polysaccaride] on the immunity and growth performance of young broilers. Trial 1 was a 28-d growth assay, in which 7-d-old broilers (n = 240) were randomly allotted to one of three dietary treatments, with eight replicate pens per treatment and ten chickens per pen. Dietary treatments included a control corn-soy-fishmeal (Treatment 1), a diet with 200 mg/kg APS (Treatment 2), and a diet with 200 mg/kg ACH (Treatment 3). Blood samples were collected by cardiac puncture on Days 7, 14, 21, and 28 for determination of serum parameters, and chickens were killed on Day 28 to measure immune organ indexes. Trial 2 was an in vitro trial to study the effects of different concentrations of polysaccharides on broiler splenocyte functions. In Trial 1, feeding either APS or ACH had no significant effects on growth performance of broilers relative to the control. However, compared to the control, feeding ACH significantly increased microhemagglutination inhibition (HI) antibody titers, bursa of Fabricius index, serum albumin, serum calcium, and nitric oxide (NO) concentrations at Day 28 (P < or = 0.05). In Trial 2, both polysaccharides showed significant immunostimulating effects. They increased NO and interleukin-2 (IL-2) production of splenocytes and enhanced splenocyte proliferation in a dose-dependent manner (P < 0.05). Those results indicate that the immunostimulating effects of APS are not as pronounced as those of ACH. Achyranthan showed immunostimulating effects in both the growth assay and in vitro studies. Therefore, ACH may be a Chinese herbal polysaccharide that has the potential to be used as a feed additive to improve broilers' immunity.

Animals↗

PubMed2003

Comparison of broiler performance when fed diets containing grain from YieldGard (MON810), YieldGard x Roundup Ready (GA21), nontransgenic control, or commercial corn.

This 42-day experiment was undertaken to compare the nutritional value of insect-protected corn event MON810 (YieldGard) and YieldGard x herbicide-tolerant corn event GA21 (Roundup Ready) to their nontransgenic controls as well as four different commercial reference corns, when fed to growing Cobb x Cobb broilers. A randomized complete block design was used, and each treatment was replicated with five pens of males and five pens of females with 10 broilers per pen. Broilers were fed approximately 55% wt/wt corn during the first 20 d and approximately 60% wt/wt corn thereafter. The corn component of diets fed to broilers was supplied entirely with grain from the eight hybrids included in the experiment. Final live weights averaged 2.09 kg/bird fed YieldGard corn and 2.15 kg/bird fed YieldGard x Roundup Ready corn and were not different (P > 0.05) from final weights for birds fed control or commercial corn. Feed conversion was not affected (P > 0.05) by YieldGard (1.72) or YieldGard x Roundup Ready (1.77) corn feeding when compared with the feeding of other corn diets. Chill weights, fat pad, thigh weights, and wing weights were not affected by diets (P > 0.05). Differences (P < 0.05) were noted for breast and drum weights across treatments. Broilers overall performed consistently and had similar carcass yield and meat composition when fed diets containing YieldGard (event MON810) or YieldGard (event MON810) x Roundup Ready (event GA21) as compared with their nontransgenic controls and commercial diets.

Animal Feed↗

PubMed2003

Components of feed efficiency in broiler breeding stock: energetics, performance, carcass composition, metabolism, and body temperature.

Two experiments were conducted to identify factors influencing feed conversion in broilers. The first experiment was conducted to develop a test for body temperature (BT) under mild handling stress. In the first experiment, BT was recorded periodically with birds briefly restrained after they had been removed from feed with either continuous lighting or 16L:8D. Body temperature was affected by photoperiod and declined following feed removal. The second experiment was conducted to investigate metabolic-physiologic differences existing between good (G) and poor (P) converting broilers, initially classified in a commercial breeding company's feed conversion (FCR) test. Basal metabolic rate (BMR) and BT were measured at the beginning and end of the FCR test following appropriate time without feed. Heat production (HP) was recorded throughout the study both for BMR calculations and to measure net energy (NE). Excreta were collected for measurement of AME, and at study termination, birds were analyzed for carcass composition. The G and P converters, however, had similar BMR and feed consumption but differed in AME (58 kcal/kg) and total NE (184 kcal/kg). Generally, G and P broilers had similar starting BW, but the G broilers gained more weight on the same amount of feed than did P broilers. The two BT measurements recorded in the present study were correlated with each other. The BT was also correlated with subsequent gain and FCR, indicating potential use as an indicator trait for feed conversion. Further, the data indicated that processes other than basal metabolism (measured as average hourly HP) may impact FCR. These might include variability in fear response during BT measurement or variations in bird activity level.

Animal Nutritional Physiological Phenomena↗

PubMed2003

The influence of temperature on the threonine and tryptophan requirements of young broiler chicks.

Two experiments were conducted to investigate the influence of a warm environment (35 degrees C) on the threonine and tryptophan requirements of young broiler chicks from 7 to 18 or 21 d of age. Seven hundred forty (experiment 1) and one thousand eight (experiment 2) 1-d-old Cobb x Cobb straight-run broiler chicks were raised in wire-floored battery brooders in moderate temperature rooms (33 to 34 degrees C). For the first 7 d, all chicks were fed a standard corn-soybean-meal-based crumbled starter diet. On d 7, six chicks each (experiment 1) and eight chicks each (experiment 2) were randomly assigned to individual pens. In experiment 1, chicks were fed a corn-peanut meal basal diet supplemented with six levels of threonine (0.630, 0.651, 0.673, 0.715, 0.758, or 0.800% of the diet). In experiment 2, chicks were fed a corn-corn gluten meal based basal diet supplemented with six levels of tryptophan (0.090, 0.115, 0.140, 0.165, 0.190, or 0.215% of the diet). Each dietary treatment was repeated with three pens in each room and three rooms at each temperature. Three rooms were set at a moderate temperature of 25 degrees C, and the other three rooms were set at a warmer temperature of 35 degrees C. Body weight gain, feed consumption, and feed conversion ratio were measured. The threonine requirements of young broiler chicks were 0.733 +/- 0.016% (R2 = 0.59) and 0.752 +/- 0.046% (R2 = 0.25) for body weight gain, and 0.744 +/- 0.016% (R2 = 0.67) and 0.722 +/- 0.016% (R2 = 0.47) for feed conversion ratio at 25 and 35 degrees C, respectively (broken-line linear model). The tryptophan requirements of young broiler chicks were 0.151 +/- 0.004% (R2 = 0.85) and 0.144 +/- 0.003% (R2 = 0.89) for body weight gain, 0.144 +/- 0.003% (R2 = 0.88) and 0.142 +/- 0.003% (R2 = 0.88) for feed consumption, and 0.146 +/- 0.005% (R2 = 0.76) and 0.127 +/- 0.002% (R2 = 0.94) for feed conversion ratio at 25 and 35 degrees C, respectively. On average, the threonine and tryptophan requirements of broiler chicks at 35 degrees C were very similar to those kept at 25 degrees C.

Aging↗

PubMed2003

Methionine and cystine requirements of slow- and fast-feathering broiler males from three to six weeks of age.

Two experiments were conducted to first determine Met then Cys needs of broilers from 3 to 6 wk of age and whether differences existed between slow-feathering (Ross x 308) and fast-feathering (Ross x 3F8) males. A corn-soybean meal diet (20.0% CP; 3,150 kcal ME/kg) with graded levels of Met or Cys was offered. The first experiment had dietary Met levels of 0.32, 0.38, 0.44, and 0.50% with surfeit Cys (0.40%). Broilers from both feathering strains responded similarly to supplemental Met. Although body weight was not responsive, F/G improved through to the highest level of dietary Met (linear, P < 0.05). Chilled carcass weight increased with Met (linear, P < 0.05) paralleling F/G; however, no differences were detected in the amount of associated abdominal fat. Breast fillet yield increased with Met to maximize at 0.48% (quadratic, P < or = 0.009). In a satellite study using the same birds in cages and feeds, N retention at d 29 maximized at 0.46% Met (quadratic, P < 0.05). The second experiment had Cys at 0.32, 0.34, 0.38, and 0.46% with Met fixed at a submarginal level of 0.38%. Increasing dietary Cys had no effect on live performance of slow-feathering birds, whereas weight gain of fast-feathering birds achieved maximum at 0.36% Cys (cubic; P < 0.05) with F/G responding similarly. Chilled carcass (cubic, P < 0.002) and breast fillet weights (cubic, P < 0.001) of fast-feathering birds also increased with Cys to maximize at 0.36%, and the amount of abdominal fat was not influenced by feathering or Cys supplementation. Separate measurement of N retention at d 31 failed to detect a difference in protein utilization attributable to feathering, but an optimum was achieved at 0.40% Cys with both broiler sources. Overall results suggest that the Met requirement for broiler males between 3 and 6 wk of age was independent of feathering and approximated 0.46% (95% of the level of maximal response). Cystine requirements once corrected for submarginal Met status indicated a greater demand by fast- than slow-feathering male broilers corresponding to 0.42 and 0.37%, respectively.

Age Factors↗

PubMed2004

Effects of deoxynivalenol on general performance and electrophysiological properties of intestinal mucosa of broiler chickens.

A feeding trial was conducted to evaluate the effects of diets contaminated with deoxynivalenol (DON on the performance of broilers and on the electro-physiological parameters of the gut. The control group was fed the starter and finisher diets without addition of DON. Another group of broilers was fed the starter and finisher diets with 10 mg/kg DON, whereas another group was fed the DON-contaminated diets supplemented with a microbial feed additive (Eubacterium sp.). The diets were provided ad libitum for 6 wk. DON had no effect (P > 0.05) on feed consumption, feed conversion, or body weight. The effect of DON on the electrophysiological parameters of the jejunum was studied in vitro using isolated gut mucosa in Ussing chambers. At the end of the feeding period, 7 birds from each group were killed, and the basal and glucose stimulated transmural potential difference (PD), short-circuit current (Isc), and electrical resistance (R) were measured in the isolated gut mucosa to characterize the electrical properties of the gut. The transmural PD did not differ (P > 0.05) among groups. The tissue resistance was greater (P < 0.05) in birds receiving DON and the microbial feed additive than in the controls and DON group. Addition of D-glucose on the luminal side of the isolated mucosa increased (P < 0.05) Isc in the control and DON-probiotic (Eubacterium sp.; PB) groups, whereas it decreased (P < 0.05) in the DON group indicating that the glucose-induced Isc was altered by DON. Addition of the eubacteria to the DON contaminated feed of the broilers led to electrophysiological properties in the gut that were comparable with those of the control group. It could be concluded that 10 mg/kg DON in the diet impaired the Na(+)-D-glucose cotransport in the jejunum of broilers. In the absence of clinical signs, and without impaired performance, DON appeared to alter the gut function of broilers. The addition of Eubacterium sp. may be useful in counteracting the toxic effects of DON on intestinal glucose transport.

Animal Feed↗

PubMed2004

Evaluation of broiler performance when fed insect-protected, control, or commercial varieties of dehulled soybean meal.

We evaluated the nutritional value of broiler diets containing approximately 35% soybean meal from insect-protected soybean containing CrylAc protein, or from a similar nontransgenic control, or from 7 reference commercial soybean varieties. The feeding trial lasted 41 d, and each treatment consisted of 10 replicates of 1-d-old Ross 508 broilers (5 pens males and 5 pens females). Each pen contained 12 birds, and at d 13, birds were randomly removed until 9 birds remained. Body weight and feed intake were measured on pen basis at 41 d. At d 42, 4 broilers per pen were slaughtered. The carcasses were dissected, and cut-up yields were determined. Dry matter, protein, and fat contents of breast meat as well as shear force of breast meat were determined. The data were analyzed by ANOVA. The BW and feed conversion ratio at d 41 averaged 2,435 g and 1.52, respectively. There were no significant treatment x sex interactions. Data for final BW, feed conversion, carcass yield, and breast meat data were not different (P < 0.05) between broilers fed insect-protected and those fed commercial soybean meal varieties. Thus, insect-protected soybean meal was nutritionally equivalent to nongenetically modified soybean varieties when fed to broilers.

Animal Feed↗

PubMed2004

Evaluation of broiler performance when fed Roundup-Ready wheat (event MON 71800), control, and commercial wheat varieties.

We evaluated the nutritional value of broiler diets containing approximately 40% wheat grain from Roundup Ready wheat (MON 71800), its similar nontransgenic control (MON 71900), or reference commercial wheat varieties. The feeding trial lasted 40 d, and each treatment consisted of 10 replicates of 1-d-old Ross 308 broilers (5 pens of males and 5 pens of females). Each pen contained 12 birds, and at d 13 birds were randomly removed until 9 birds remained. Body weight and feed intake were measured on pen basis at 40 d. At d 41, four broilers per pen were slaughtered. The carcasses were dissected, and cut-up yields were determined. Dry matter, protein, and fat contents of breast meat were determined. The data were analyzed by an ANOVA procedure. The BW and feed conversion at d 40 averaged 2,450 g and 1.52, respectively. There were no significant treatment x sex interactions, except for evisceration yield with significant differences (P < 0.05) in yield between birds fed 2 commercial wheat varieties. Data for final BW, feed conversion, carcass yield, and breast meat were not statistically different (P < 0.05) between broilers fed MON 71800 or MON 71900 or the population of birds fed commercial wheat varieties, except a lower carcass yield at d 41 for birds fed the nontransgenic control wheat. Thus MON 71800 was nutritionally equivalent to nongenetically modified wheat varieties when fed to broilers.

Animal Feed↗

PubMed2004

Reduction of ascites mortality in broilers by coenzyme Q10.

Effects of coenzyme Q10 (CoQ10) supplementation on growth performance and ascites were studied in broilers. One hundred eighty 1-d-old Arbor Acre male broiler chicks were randomly allocated into 3 groups with 6 replicates each. From d 8, the diets were supplemented with CoQ10 at levels of 0, 20, and 40 mg/kg, respectively. From d 15 to 21, all the chicks were exposed to low ambient temperature (15 to 18 degrees C) to induce ascites. Average feed intake, BW gain, and feed conversion ratio of the broilers during 0 to 3 wk, 3 to 6 wk, and 0 to 6 wk were measured. The results showed that there were no influences observed on broilers' growth performance, but the mortality due to ascites was reduced by CoQ10 supplementation (P < or = 0.05). Erythrocyte osmotic fragility (EOF) was significantly decreased by 40 mg/kg CoQ10 compared with the control, but no significant changes were observed on blood packed cell volume (PCV) among the treatments. Pulmonary arterial diastolic pressure was significantly decreased on d 36, but no significant changes were observed on right ventricular pressure (RVP), pulmonary arterial systolic pressure, and the maximum change ratio of right intraventricular pressure (+/- dp/ dtmax). Ascites heart index (AHI) was significantly decreased by 40 mg/kg CoQ10 supplementation (P < or = 0.05). The results of this study suggested that CoQ10 has a beneficial effect in reducing ascites mortality in broilers, and 40 mg/kg CoQ10 seems to be more effective than 20 mg/ kg CoQ10.

Animal Feed↗

PubMed2005

Effects of feeding ervil (Vicia ervilia) seeds soaked in water or acetic acid on performance and internal organ size of broilers and production and egg quality of laying hens.

Experiment 1 was conducted to study the effects of feeding 60% untreated ervil seeds (UE) or ervil soaked in water at room temperature (RTWE) or at 40 degrees C (40WE) for 72 h with water change every 12 h on the performance and internal organ size of broilers. Isocaloric and isonitrogenous corn-soybean meal diet (control) and diets containing 60% UE, RTWE, or 40WE were fed to battery caged broilers in 4 replicates with 8 birds per replicate, from 8 to 49 d. Broilers consuming UE from 8 to 28 d gained less weight, used feed less efficiently, and had heavier liver, pancreas, and gall bladder weights (%BW) than the other treatments (P < 0.05). Compared with control birds, broilers on 40WE had similar relative organ weights, except for kidney, but lower BW gain at 49 d (P < 0.05). In experiment 2, ervil seeds were soaked in 1% acetic acid at room temperature (RTAAE) or at 40 degrees C (40AAE) for 24 h. A conventional diet and diets containing 60% UE, 40WE, RTAAE, or 40AAE were fed to individually caged laying hens in 4 replicates per treatment with 5 hens per replicate for 42 d. Hens on UE had the poorest performance followed by RTAAE, 40WE, and then 40AAE (P < 0.05). Compared with the control, all treated ervil diets resulted in lower shell thickness values but higher Haugh unit scores (P < 0.05). In experiment 3, 30% dietary UE and 40AAE at 10, 20, and 30% were fed to layers for 56 d. The general performance of hens on 30% 40AAE was comparable with that of the control except for BW and feed conversion (P < 0.05). Compared with UE, the performance of broilers and layers was improved by 40WE and that of hens was further enhanced by 40AAE. In addition, diets containing up to 20% 40AAE had no adverse effects on feed conversion, egg production, or quality of hens.

Acetic Acid↗

PubMed2005

A comparison of two sources of phytase in liquid and dry forms in broilers.

Research with corn-soybean meal diets was conducted to compare phytase sources in commercial broilers. A Ca to nonphytate P (nPP) ratio of 2.5:1 was maintained in all diets. Experiments 1 and 2 were conducted from d 4 to 13 (experiment 1) or d 9 to 23 post-hatching (experiment 2) in batteries. The 10 treatments used in both experiment were: Diets 1 to 4 = 0.20, 0.25, 0.30, or 0.35% nPP; Diets 5 to 7 = diet 1 plus 100, 200, or 300 phytase units/kg of diet from Natuphos (NAT); and Diets 8 to 10 = diet 1 plus 100, 200, or 300 phytase units/ kg of diet from Ronozyme (RON). As nPP levels increased, daily gain (ADG), feed intake (ADFI), gain:feed, and toe and tibia ash percentage were linearly increased (P < 0.06) in experiments 1 and 2. Incremental addition of phytase, regardless of source, linearly increased (P < 0.07) ADG and ADFI in experiment 1. Broilers fed NAT had higher (P < 0.07) toe ash percentage in experiment 1 and 2, and higher (P < 0.02) ADG and ADFI in experiment 2 than those fed RON. In experiment 3, 3,360 broilers were used to test 2 dry phytase products from 0 to 41 d posthatching in a 3-phase feeding program. The treatments were: Diet 1) adequate Ca and nPP; Diet 2) nPP reduced by 0.20%; Diets 3 to 5 = diet 2 plus 300, 500, or 750 phytase units/kg of diet from NAT; and Diets 6 to 8 = Diet 2 plus 300, 500, or 750 phytase units/kg of diet from RON. Broilers fed the adequate Ca and nPP diet had improved ADG and ADFI overall, and tibia ash weight and percentage in all growth phases (P < 0.03) compared with those fed the reduced Ca and nPP diets. Overall, ADG and ADFI were linearly increased (P < 0.05) by incremental phytase addition in experiment 3. Both NAT and RON produce similar growth and bone ash traits in commercial broilers.

6-Phytase↗

PubMed2005

Evaluation of transgenic hybrid corn (VIP3A) in broiler chickens.

A 49-d feeding study evaluated whether standard broiler diets prepared with Syngenta Seeds VIP3A transgenic derived corn grain had any unanticipated adverse effects on male or female broiler chickens as compared with diets prepared with nontransgenic (isoline) control corn grain. Two commercial lots of grain grown in North Carolina during the 1999 (NC 1999) and 2000 (NC 2000) seasons were included for reference purposes. Broiler growth was excellent with males reaching 3466 g and females reaching 2882 g at 49 d of age. Final BW of the VIP3A, isoline, and NC 1999 corn groups were within 21.1 g, whereas the NC 2000 group was 42.4 g lower than the lowest of this group. There was no overall corn source effect on adjusted feed conversion ratio (FCR) or mortality to 49 d of age. Carcass analysis demonstrated no differences in percentage yield due to corn source among males and females other than percentage wings in females. Comprehensive clinical chemical analyses of blood taken from representative birds at 49 d of age showed no differences due to corn sources. The transgenic VIP3A hybrid diets numerically supported the most rapid broiler chicken growth, the second lowest mortality rate and best FCR, without practical differences in carcass yield. The few differences found in this study were not unique to a given corn source but instead appeared to be distributed equally across the diet groups evaluated in the study. Although it was not clear whether small differences in performance were attributable to the transgenic corn per se or were due to possible slight differences in overall composition of the formulated diets, it was clear that the transgenic corn had no deleterious effects on broiler performance and carcass yield in this study.

Animal Feed↗

PubMed2005

Glutathione and respiratory chain complex activity in duodenal mitochondria of broilers with low and high feed efficiency.

We previously observed increased reactive oxygen species (ROS) production in intestinal mitochondria obtained from broiler breeder males with low feed efficiency (FE, gain-to-feed). Because antioxidants are critical for combating ROS-mediated oxidative stress and preserving mitochondrial function, the objectives of this study were 1) to determine levels of reduced glutathione (GSH), a major antioxidant in mitochondria, 2) to measure activities of GSH recycling enzymes: GSH peroxidase and GSH reductase, and 3) to establish relationships between antioxidants and respiratory chain complex activities (complexes I, II, III, IV, and V) in broiler breeder males with low and high FE. Duodenal mitochondria were isolated from broilers with low (0.62 +/- 0.01, n = 8) and high (0.80 +/- 0.01, n = 8) FE. Activities of respiratory chain complexes, GSH peroxidase, and GSH reductase, and levels of GSH were measured by UV spectrophotometry. There were no differences in GSH peroxidase or reductase activities or in individual complex activities between groups but GSH levels tended to be higher (P = 0.075) and oxidized to reduced glutathione ratio tended to be lower (P = 0.077) in broilers with high FE. Regression analysis revealed significant correlations (P < or = 0.05) between mitochondrial GSH and activities of complexes II, IV, and V with R2 values of 0.35, 0.56, and 0.49, respectively. These data suggest that GSH may be important in maintaining or enhancing the activity of certain respiratory chain complexes and could be involved in the phenotypic expression of feed efficiency in broilers.

Animals↗

PubMed2005

Comparison of inorganic and organic selenium sources for broilers.

An experiment was conducted to compare the effects of organic and inorganic sources of Se on growth performance, carcass traits, breast and plasma Se concentrations, and plasma glutathione peroxidase (pGPX3) activity in broilers. Broiler chicks were sexed on d 0 and within sex, randomly allotted to dietary treatment. Average initial and final BW of the broilers were 47 and 2,684 g, and the experiment lasted 49 d. A 3-phase feeding program similar to industry recommendations was used, and the basal diets for each phase were corn-soybean meal based. For each growth phase, the basal diet was supplemented with 0 (control) or 0.30 ppm Se from sodium selenite (SS) or Se-enriched yeast (SY). Each treatment was replicated 7 times (4 pens of males and 3 pens of females) with 50 male or 55 female broilers per replicate. Daily gain, feed intake, gain:feed, eviscerated and chill weights, carcass yield, breast weight, and moisture loss from the breast were not affected (P > 0.05) by Se supplementation. Dietary supplementation with SY increased (P < 0.05) muscle and plasma Se concentrations compared with broilers fed the control diet or the diet with SS. Plasma GPX3 activity was not affected (P > 0.05) by Se source or concentration. The results from this experiment indicate that organic Se increases tissue Se concentration, but it does not affect growth performance, carcass traits, or pGPX3 activity compared with inorganic Se.

Animal Nutritional Physiological Phenomena↗

PubMed2005

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.

Animals↗

PubMed2005

Effect of butyric acid on the performance and carcass yield of broiler chickens.

Short-chain fatty acids such as butyrate are considered potential alternatives to antibiotic growth promoters. The efficacy of butyric acid on performance and carcass characteristics of broiler chickens was tested in two studies. The effect of dietary butyrate on the ability to withstand coccidial oocyte challenge also was investigated. In experiment 1, male broiler chickens were fed diets supplemented with 0 or 11 ppm virginiamycin or 0.2 or 0.4% butyric acid (as mono-, di-, and triglyceride). In experiment 2, broilers were fed bacitracin methylene disalicylate or 0.1 or 0.2% butyric acid. In another trial, birds vaccinated against coccidiosis were challenged with oocytes at 21 d and examined 6 d later. In experiment 1, diet treatments had no effect on body weight gain. Feed intake of the birds fed 0.4% butyric acid was decreased (P < 0.01) compared with birds fed the nonmedicated diet during the starter period, whereas birds fed 0.2% butyric acid had similar feed intake to the control birds. In experiment 2, diet treatments did not affect the performance of broiler chicks while carcass weight and breast meat yield increased (P < 0.01) in birds fed 0.2% butyric acid. With oocyte challenge, birds that had received butyric acid before challenge showed higher growth rate following the challenge compared with birds that received nonmedicated feed. Bacitracin decreased (P < 0.05%) duodenal villi crypt depth, whereas villus length was similar in birds fed butyric acid or the nonmedicated control diet. These results show that 0.2% butyric acid can help to maintain the performance and carcass quality of broilers, especially in vaccinated birds challenged with coccidiosis.

Animals↗

PubMed2005

Comparison of three lines of broiler breeders differing in ascites susceptibility or growth rate. 1. Relationship between acoustic resonance data and embryonic or hatching parameters.

Ascites is a prevalent cardiovascular disease among modern broilers with negative impacts on production and animal welfare. The peak of mortality due to ascites occurs at the end of the growing period, but the etiology of this problem may start during embryonic development. A few recent reports have demonstrated that the signs of ascites susceptibility are manifested during the late stages of incubation. In the current study, we used a nondestructive method based on egg acoustic resonance parameters [resonant frequency (RF) and damping] to establish a relationship between embryo physiological events during early development in broiler eggs and susceptibility to ascites. The hatching eggs of 3 broiler lines differing in ascites susceptibility were used for this study: ascites-resistant dam line (DAR), ascites-sensitive dam line (DAS), and ascites-sensitive sire line (SASL). These lines were selected on the basis of fast growth, high breast meat yield, and ascites induction at low temperatures such that the order of ascites susceptibility in terms of mortality was SASL >> DAS > DAR. Eggs were incubated under standard conditions in forced-draft incubators. We measured egg weights at setting, albumen pH, Haugh units (HU) at setting, and embryo weights at d 11 and 18, at internal pipping (IP), and at hatch. The durations of IP, external pipping (EP), and hatching were also determined. At 2 hourly periods during incubation, egg RF and damping were also measured. There were differences in egg weights between DAR and SASL vs. DAS, but albumen HU, albumen pH, and the ratio of yolk weight to egg weight were similar. There were differences in RF, damping, embryonic growth rates, and hatching events. Changes in resonant frequency and damping, which certainly suggest eggshell differences among lines, were not totally related to variations in physiological events during early and late embryonic development. A comparison between DAR and DAS, between DAS and SASL, or DAR and SASL indicates that sensitivity to ascites and selection for rapid growth rate in ascites-sensitive lines have different effects on embryonic parameters. We concluded that the sensitivity of broiler breeders to ascites does not influence egg internal quality, but the occurrence of ascites sensitivity in broilers could not be reliably predicted by early in ovo acoustic resonance parameters and hatching events.

Acoustics↗