Energy and protein utilisation by broiler chickens fed diets containing cottonseed meal and supplemented with a composite enzyme product.

1. The present study examined the potential of new-generation microbial enzymes to improve the utilisation of energy and protein of cottonseed meal (CSM)-containing diets, with the aim of increasing its inclusion level in broiler chickens diets. 2. Four hundred and eighty, one-day-old Ross 308 male broilers were used to assess the utilisation of energy and protein by broiler chickens fed diets containing four graded levels of CSM - none, low (4, 8, 12%), medium (5, 10, 15%) or high (6, 12, 18%) in the starter, grower, and finisher phases, respectively, supplemented with 100 mg/kg of a composite enzyme product (xylanase and ß-glucanase). 3. Inclusion of CSM improved (P < 0.01) apparent metabolisable energy (AME), with further improvement (P < 0.001) seen in the enzyme-supplemented diets. Inclusion of CSM reduced (P = 0.002) the metabolisable energy intake (MEI), but this was increased (P < 0.05) with enzyme supplementation. 4. Enzyme addition increased (P < 0.001) the net energy of production (NEp), while heat production (HP) decreased (P < 0.001) with CSM inclusion. More energy was retained as fat (P < 0.05) and protein in birds fed diets with the enzyme, but this was reduced (P < 0.029) by CSM. 5. There was an increase (P < 0.05) in efficiencies of ME use for energy, lipid and protein retention, with higher CSM levels. The enzyme improved (P < 0.013) efficiency of ME use for lipid retention. 6. Feeding diets containing CSM to the broilers enhanced (P < 0.05) protein intake (PI) and protein efficiency ratio (PER). Positive effects (P < 0.05) of enzyme were observed on protein gain (PG) and net protein utilisation (NPU). 7. Results obtained from this study suggested that nutrient utilisation of diets containing CSM by broiler chickens can be improved by enzyme supplementation.

Dietary hydrolysed yeast cell wall extract is comparable to antibiotics in the control of subclinical necrotic enteritis in broiler chickens.

1. The aim of this study was to examine the effect of yeast cell wall (YCW) on performance and physiological responses of broiler chickens under subclinical necrotic enteritis challenge.2. Six treatments in a 2 × 3 factorial arrangement (non-challenged or challenged plus no supplement, YCW or antibiotics (AB)) was used. Each treatment was replicated eight times with 12 birds per replicate. The treatments included: (1) Positive control (PC; no additive, not challenged); (2) Negative control (NC; no additive, with challenge); (3) YCWN = yeast cell wall (2.0 g/kg diet, not challenged; (4) YCWC = yeast cell wall (2.0 g/kg diet, challenged); (5) ABN = zinc bacitracin 50 ppm + Salinomycin 60 ppm, not challenged); (6) ABC = zinc bacitracin 50 ppm + Salinomycin 60 ppm, challenged).3. Eimeria challenge at 9 d of age did not affect feed intake (FI), body weight gain (BWG), FCR or liveability at 10 d. The BWG and FCR at 10 d were greater (P < 0.05) in birds fed YCW or AB (AB) diets relative to the PC or NC groups. On 24 and 35 d, FI, BWG, FCR and flock uniformity (28 d) were greater (P < 0.05) in the challenged groups fed YCW or AB diets compared to NC group.4. Supplementation with YCW ameliorated the negative effects of NE on liver, spleen and bursa weight of birds.5. Necrotic enteritis challenge decreased (P < 0.05) caecal Lactobacillus and Bifidobacterium spp. counts, and increased ileum lesion score and caecal Clostridium perfirngens counts. This was reversed by the addition of either YCW or AB.6. Supplementation with YCW and AB resulted to a greater (P < 0.05) dressing percentage and meat yield (35 d).7. The results indicated that YCW plays a vital role in improving the physiological response and performance of broiler chickens under subclinical necrotic enteritis challenge.

Supplementation of broiler diets with high levels of microbial protease and phytase enables partial replacement of commercial soybean meal with raw, full-fat soybean.

A 3 × 3 + 1 factorial, involving three levels of protease (0, 15,000 or 30,000 PROT/kg) and three levels of phytase (1,000, 2,000 or 3,000 FYT/kg), was used to evaluate the effect of replacing commercial soybean meal (SBM) with raw, full-fat soybean (RFSB) at 75 g/kg of diet for broilers. A control diet was used for comparison. Each treatment was replicated six times, with nine birds per replicate. The concentration of trypsin inhibitors (TIs) in the test diets was approximately 10,193.4 TIU/kg. Regardless of enzyme supplementation, feed intake (FI) and body weight gain (BWG) of birds in the control group were superior to those on the test diets. Birds that received the protease-free test diets had reduced FI and BWG, but when supplemented with protease, were similar to the control diet in BWG, FI (except 0-35 days) and feed conversion ratio (FCR). When the test diet was supplemented with elevated levels (extradose) of protease and phytase, the BWG was improved during 0-10 days (p = .05) and 0-24 days (p < .01). Regardless of protease supplementation, the weight of thighs was lower for birds fed the test diets. Birds that received the control diet had smaller weight of pancreas. Increasing the level of phytase supplementation reduced (p < .05) the weight of the pancreas. The apparent ileal digestibility (AID) of CP and AA was higher in birds on the control diets, but this was also improved in test diets by protease supplementation. The activities of trypsin (7%), general proteolytic (11%) and lipase (12%) were slightly increased because of protease supplementation. Mucosal depth and apparent villus surface areas were increased by about 2.9% and 20%, respectively, due to supplementation of elevated level of phytase. It can be concluded that RFSB could partially replace SBM in broiler diets, provided the diets are supplemented with elevated levels of protease and phytase.

Physiological and health-related response of broiler chickens fed diets containing raw, full-fat soya bean meal supplemented with microbial protease.

A 2 × 3 factorial study (protease: 0 or 1,5000 PROT/kg and raw full-fat soya bean meal [RSBM] replacing the commercial SBM at 0, 45 and 75 g/kg of diet) was conducted to examine the performance of broilers. Phytase (2000 FYT/kg) was uniformly added to each diet, each also replicated six times, with eight birds per replicate. Birds were raised in climate-controlled rooms using sawdust as the bedding material and offered starter, grower and finisher diets. Feed intake (FI) and body weight gain (BWG) were reduced (p < .05) due to increasing levels of RSBM, but feed conversion ratio (FCR; 0-35 days) was unaffected. Over the first 24 days, neither RSBM nor protease supplementation affected (p > .05) mortality, footpad dermatitis or intestinal lesions in birds. At day 24, the weight, length, width and strength of tibia bone were reduced in chickens that received an elevated level of RSBM (75 g/kg of diet), but this was not significant at day 35. At day 24 (p < .05) and 35 (p < .01), Ca concentration in the litter was reduced when the RSBM level was increased in the diet, but P content was not affected. On days 24 (p < .05) and 35 (p < .01), the N content in litter was also increased with increase in dietary RSBM. Protease supplementation increased (p < .05) the uric acid concentration in the litter (at day 35), but the reverse was the case for ammonia concentration. Overall, the results of this study indicate that there are no major health-related risks, associated with the replacement of commercial SBM with RSBM (≤25%) in broiler diets.

Increased iron level in phytase-supplemented diets reduces performance and nutrient utilisation in broiler chickens.

1. The effect of different levels of dietary iron on phytase activity and its subsequent effect on broiler performance were investigated in a 3 × 2 factorial arrangement. A total of 360 day-old Ross 308 male broiler chicks were distributed to 6 experimental diets, formulated with three levels of Fe (60, 80 and 100 mg/kg) and two levels of phytase (0 and 500 FTU/kg). 2. Phytase supplemented to mid-Fe diets increased feed consumption more than the non-supplemented diet at d 24. From hatch to d 35, Fe × phytase interaction significantly influenced the feed intake (FI), body weight gain (BWG) and feed conversion ratio (FCR). The high-Fe diet supplemented with phytase significantly reduced FI and BWG of broilers than those supplemented with low- or mid-Fe diets. The overall FCR was significantly better in birds fed on the mid-Fe diets with phytase supplementation. 3. A significant improvement in ileal digestibility of N, P, Mg and Fe was observed in birds feed diets containing 60 mg Fe/kg, with significant interaction between Fe and phytase. 4. Phytase improved the bone breaking strength when supplemented to low- or mid-Fe diets, compared to the non-supplemented diets. There was a significant Fe × phytase interaction effect. Tibia Fe content was higher in birds fed on phytase-free diets with high Fe but the reverse was the case when phytase was added and their interaction was significant. High dietary Fe significantly increased the accumulation of Fe in liver. 5. Phytase improved Ca-Mg-ATPase, Ca-ATPase and Mg-ATPase activities in jejunum when supplemented to the diet containing 80 mg Fe/kg. 6. This study indicates that high (100 mg/kg) dietary Fe inhibited phytase efficacy and subsequently reduced the overall performance and nutrient utilisation of broilers.

Physico-chemical properties of late-incubation egg amniotic fluid and a potential in ovo feed supplement.

OBJECTIVE: This study explored the physico-chemical properties of late-incubation egg amniotic fluid and a potential in ovo feed (IOF) supplement. METHODS: Amniotic fluid was collected from broiler breeders (Ross 308, 51 weeks and Cobb 500, 35 weeks) on day 17 after incubation. A mixture of high-quality soy protein supplement - Hamlet Protein AviStart (HPA) was serially diluted in MilliQ water to obtain solutions ranging from 150 to 9.375 mg/mL. The mixtures were heat-treated (0, 30, 60 minutes) in a waterbath (80°C) and then centrifuged to obtain supernatants. The amniotic fluid and HPA supernatants were analysed for their physico-chemical properties. RESULTS: Only viscosity and K+ were significantly (p<0.05) different in both strains. Of all essential amino acids, leucine and lysine were in the highest concentration in both strains. The osmolality, viscosity and pCO2 of the supernatants decreased (p<0.05) with decreasing HPA concentration. Heat treatment significantly (p<0.05) affected osmolality, pH, and pCO2, of the supernatants. The interactions between HPA concentration and heat treatment were significant with regards to osmolality (p<0.01), pH (p<0.01), pCO2 (p<0.05), glucose (p<0.05), lactate (p<0.01) and acid-base status (p<0.01) of HPA solutions. The Ca2+, K+, glucose, and lactate increased with increasing concentration of HPA solution. The protein content of HPA solutions decreased (p<0.05) with reduced HPA solution concentrations. The supernatant from 150 mg/mL HPA solution was richest in glutamic acid, aspartic acid, arginine and lysine. Amino acids concentrations were reduced (p<0.05) with each serial dilution but increased with longer heating. CONCLUSION: The values obtained in the primary solution (highest concentration) are close to the profiles of high-protein ingredients. This supplement, as a solution, hence, may be suitable for use as an IOF supplement and should be tested for this potential.

Response of broiler chickens to different levels of calcium, non-phytate phosphorus and phytase.

1. Five hundred and seventy six-d old Ross 308 broiler chicks (6 cages per diet, 8 birds per cage in 3 × 2 × 2 factorial arrangement) were fed on maize-soybean meal-based diets containing three concentrations of Ca (6, 8 or 10 g/kg), two concentrations of non-phytate phosphorus (NPP) (3 or 4 g/kg) and two levels of exogenous microbial phytase (0 or 500 FTU/kg) from d 0 to 35. 2. Body weight (BW), feed intake (FI) and mortality records were collected. Two birds per replicate were killed at 24 d of age to obtain tibia samples. 3. Increasing Ca level significantly reduced the FI and body weight gain (BWG) between hatch and 10 and 24 d, especially with the phytase-supplemented diets. However, phytase supplementation of the diet containing 4 g NPP/kg improved the FI and BWG at d 10 and 24. At d 24, phytase supplementation improved feed conversion ratio (FCR) of birds that consumed diets containing high NPP. The overall FCR was better in birds offered the phytase-supplemented, medium-Ca diet. 4. There was a significant reduction in length, width and breaking strength of the tibia bone in birds fed on a diet with high Ca and low NPP. Phytase supplementation improved the tibia ash content and bone breaking strength of chicks fed on the diet containing 8 and 4 g/kg Ca and NPP, respectively. The Ca content of the tibia bone was low in birds fed on diets with 6 and 4 g/kg Ca and NPP, respectively, but this was counteracted by phytase supplementation. 5. Birds fed on diets with 4 g/kg NPP had the best carcass percentage and parts yield. Phytase supplementation to high-Ca diets significantly reduced the carcass yield of birds. 6. These results confirmed the detrimental effect of high dietary Ca on phytase activity and subsequent growth and bone development of birds, especially when NPP is in short supply.

Effect of dietary inclusion of spray-dried porcine plasma on performance, some physiological and immunological response of broiler chickens challenged with Salmonella sofia.

This study was conducted to investigate the effect of spray-dried porcine plasma (SDPP) in broiler chickens under Salmonella sofia disease challenge. The experiment comprised five starter diets: positive control (no supplement), diet supplemented with in-feed antibiotics (IFA; salinomycin 0.05% + zinc bacitracin 0.033%) and diets supplemented with SDPP at 10 or 20 g/kg diet. All four of these groups were challenged with S. sofia, while a fifth group was unchallenged and used as the negative control. The experimental diets were fed to 14 days; then, the birds were switched to commercial-type grower and finisher diets. Oral inoculation of the challenged groups with S. sofia occurred on day 8, 10 and 12. Body weight was significantly higher in the birds fed diets containing IFA and SDPP than in the challenged control group, but it was only significant in starter and grower phases. In general, there was an improvement in the weights of the immune-related organs, but it was only significant for the weight of the bursa of SDPP-fed birds at 13 days. At day 13, blood potassium content was lower and the concentrations of IgG and IgM tended to be lower in the birds fed on low-SDPP starter diets than those of the other groups. There were significant differences in the concentration of lactic acid in the ileum and acetic acid, formic acid, butyric acid and propionic acid in the caeca. Inclusion of SDPP to the starter diets of broiler chicks had positive effects on broiler performance, immunity and gut health during exposure to highly pathogenic conditions.

Standardized ileal amino acid digestibility of expeller-extracted canola meal subjected to different processing conditions for starter and grower broiler chickens.

Six expeller-extracted canola meal (ECM) samples produced under different seed conditioning temperatures (90, 95, or 100°C) and screw torques in the second press (low or high) were evaluated in a 3 × 2 factorial arrangement of treatments to determine the effect of processing on standardized ileal amino acid digestibility (SID) in 10 and 24-day-old broilers. A nitrogen-free diet was fed to determine ileal endogenous amino acid flow. Each diet was fed for 5 d to 6 replicate cages of 10 or 7 chicks, and ileal samples were collected at 10 and 24 d, respectively. The endogenous flow (mg/kg DM intake) of CP and all amino acids except Cys decreased (P < 0.01) with age. Conditioning temperature by screw torque interactions were detected (P < 0.05) for apparent ileal digestibility (AID) of CP, Arg, Ile, Lys, Phe, Thr, Ala, Asp, Glu, Pro ,and Ser at d 10, and the same trend was observed at d 24 except for Ile, Phe, Ala, and Pro (P > 0.05). Meals processed under medium conditioning temperature (95°C) at either low or high screw torque had the greatest (P < 0.05) AID of CP and total amino acids. The SID values followed a similar pattern as AID at both ages. When corrected for endogenous losses, the average AID of total amino acids improved approximately 3.5 and 2.0 units, at 10 and 24 d, respectively. The AID and SID values increased (P < 0.05) with age for most AA, but the effect of age was not consistent between ECMs. A negative correlation was detected between NDF and neutral detergent-insoluble nitrogen (NDIN) content of the meals and SID values of Lys at d 24 (r = -0.79, r = -0.76; P = 0.001, respectively). Processing conditions affected CP and amino acid digestibility, likely because of alterations to the chemical composition of ECM and formation of indigestible complexes of amino acids with fiber. The AID and SID values increased with age independent of meal processing conditions.

Subsequent growth performance and digestive physiology of broilers fed on starter diets containing spray-dried porcine plasma as a substitute for meat meal.

A 4 × 2 factorial experiment was conducted to investigate the effect of inclusion of spray-dried porcine plasma (SDPP), in lieu of meat meal, in the starter diet on performance and digestive physiology of broiler chickens between hatch and 35 d of age. Four levels of SDPP (0, 5, 10 or 20 g/kg) were included in the starter diets in lieu of meat meal on either wheat- or maize-based diets. Over the first 10 d, and throughout the 35-d experimental period, birds gained more body weight with increasing concentrations of SDPP regardless to the type of grain used. Inclusion of SDPP in the starter diet markedly improved feed per gain in the starter phase and across the 35-d study. There was no significant effect of the type of grain and its interaction with SDPP on the body weight gain and feed per gain for the two assessed periods. At d 10, the relative weight of the gizzard+proventriculus, spleen and liver increased with increasing concentrations of SDPP. At 24 d of age, the grain and SDPP inclusion significantly interacted, depressing the weight of bursa and spleen in birds that received the highest concentration of SDPP in the maize-based diet. Birds fed on the maize-based diets had higher relative weight of pancreas than those on the wheat-based diets. Increasing concentrations of SDPP in the starter diet improved the activities of maltase, sucrase and alkaline phosphatase at 24 d of age. The interaction of grain and SDPP concentration was significant for sucrase activity in birds on the wheat-based diets. Chickens on maize-based diets had higher alkaline phosphatase and maltase activities than those on wheat-based diets. Chicks that were offered SDPP-containing starter diets had longer villi, deeper crypts and lower villi/crypt than the control at 24 d of age regardless of the grain type used. Furthermore, longer villi and larger villi/crypt were found in chicken groups fed on wheat-based diets than those on maize-based diets. Chickens on maize-based diets had higher dressing percentage and relative breast weight than those on wheat-based diets at 35 d of age. It can be concluded that supplementation of starter diets with SDPP would be beneficial to the long-term growth of broiler chickens. The effect of the basal grain used in the diet is minimal.

Energy Value of Cassava Products in Broiler Chicken Diets with or without Enzyme Supplementation.

This study investigated the metabolizable energy (ME) intake, net energy of production (NEp), heat production (HP), efficiencies of ME use for energy, lipid and protein retention as well as the performance of broiler chickens fed diets based on cassava chips or pellets with or without supplementation with an enzyme product containing xylanase, amylase, protease and phytase. The two products, cassava chips and pellets, were analysed for nutrient composition prior to feed formulation. The cassava chips and pellets contained 2.2% and 2.1% crude protein; 1.2% and 1.5% crude fat; and 75.1% and 67.8% starch, respectively. Lysine and methionine were 0.077%, 0.075%, and 0.017%, 0.020% protein material, respectively, while calculated ME was 12.6 and 11.7 MJ/kg, respectively. Feed intake to day 21 was lower (p<0.01) on the diet containing cassava chips compared to diets with cassava pellets. Enzyme supplementation increased (p<0.01) feed intake on all diets. Live weight at day 21 was significantly (p<0.01) reduced on the diet based on cassava chips compared to pellets, but an improvement (p<0.01) was noticed with the enzyme supplementation. Metabolizable energy intake was reduced (p<0.01) by both cassava chips and pellets, but was increased (p<0.01) on all diets by enzyme supplementation. The NEp was higher (p<0.01) in the maize-based diets than the diets containing cassava. Enzyme supplementation improved (p<0.01) NEp in all the diets. Heat production was highest (p<0.01) on diets containing cassava pellets than on cassava chips. It is possible to use cassava pellets in diets for broiler chickens at a level close to 50% of the diet to reduce cost of production, and the nutritive value of such diets can be improved through supplementation of enzyme products containing carbohydrases, protease, and phytase.

Apparent metabolizable energy value of expeller-extracted canola meal subjected to different processing conditions for growing broiler chickens.

The objective of this study was to investigate the effect of processing conditions and chemical composition on ileal digestible energy (IDE), AME, and AMEn of 6 expeller-extracted canola meal (ECM) samples subjected to conditioning temperature at 90, 95, or 100°C and high or low screw torque over the second presses in a 3 × 2 factorial arrangement. The ECM samples were incorporated into a corn-soybean meal reference diet at 30% by replacing energy-yielding ingredients. A total of 210 one-day-old male broiler chicks (Ross 308) were fed common starter and grower diets until d 18, and then assigned to 7 experimental diets replicated 6 times, with 5 chicks per cage. After a 5-d diet acclimation period from d 18 to 22, excreta was collected for 72 h. The difference method was used to determine AME, which was corrected to zero N balance to obtain AMEn. Medium seed conditioning temperature resulted in the highest IDE, AME, and AMEn compared with low or high temperature, and high screw torque resulted in higher energy utilization compared with low torque (P < 0.001). There was also an interaction (P < 0.001) between conditioning temperature and screw torque. For ECM subjected to low or medium conditioning temperature at low screw torque, IDE, AME, and AMEn values ranging from 2,137 to 2,705, 2,089 to 2,655, and 1,977 to 2,482 kcal/kg of DM, respectively, were obtained. The mean AMEn values were 2,260 kcal/kg of DM, indicating a 7% reduction compared with AME values. The AMEn values were negatively correlated with neutral detergent fiber (NDF; r = -0.93; P = 0.001) and NDIN (r = -0.87; P = 0.001). Stepwise regression to predict AMEn value resulted in the following equation: AMEn (kcal/kg of DM) = 3,397.8 + (-100.1 × NDF %) + (279.5 × ash %) + (-33.8 × ADF %) (R² = 0.91; SE = 61.9; P = 0.001). These results indicate that AMEn values vary markedly among ECM samples, and chemical constituents, especially the fiber components, may have a considerable effect on AMEn value.

Effect of sorghum distillers dried grains with solubles and microbial enzymes on metabolizable and net energy values of broiler diets.

There is generally no information regarding the influence of distillers dried grains with solubles (DDGS) on the net energy (NE) value of broiler diets. It was hypothesized that the ME content of DDGS may overestimate its productive energy, leading to higher heat increment when used in broiler diets. Furthermore, it was of interest to investigate the potential benefits of a mixture of carbohydrases and protease on energy partitioning in diets containing DDGS. In this study, 2 evaluations, comparative slaughter (CS) or indirect calorimetry (IC), were conducted using the same batch of birds and feed. Two levels of DDGS (0 or 30%) without or with an enzyme mixture were used in a 2 × 2 factorial arrangement of treatments. The CS evaluation used 240 male Ross 308 broiler chicks with 6 replicates (10 birds each) per treatment from d 18 to 28. Carcass energy values were examined in 2 birds per replicate on each of d 18 and 28 to determine heat production (HP), NE, and ME. The IC evaluation used 32 birds acclimatized to 16 closed-circuit calorimeters (2 birds per chamber) following energy partitioning measurement by gaseous exchange and total excreta collection from 18 to 24 d. Birds fed DDGS had increased feed efficiency during starter and grower phases (P < 0.001). The CS showed no difference in HP between birds fed diets with or without DDGS. When measured by IC, birds fed diets containing DDGS had higher HP and lower NE (P < 0.01). Enzyme supplementation had no effect on HP, ME, or NE:ME ratio measured using CS or IC but increased NE and NE intake (P < 0.01) from d 18 to 28. Carcass fat retention was decreased (P < 0.05) and there was a lower NE (P < 0.01) in birds fed the DDGS-diets. This study showed that 30% dietary DDGS affects energy partitioning in broilers with more heat produced, decreased dietary NE, and less fat retained in the carcass.

Effect of production phase on growth, enzyme activities and feed selection of broilers raised on vegetable protein diet.

This study consisted of two experiments, conducted to assess the impact of phase at which vegetable protein (VP) diets are introduced to broiler chicks, and preference of birds for diets based on soybean or canola meal (CM). Two hundred and ten day-old Cobb 500 chicks were randomly distributed into five dietary groups in the main experiment. One group was fed on animal protein (AP) diet all through to 21 days of age; two other groups were started on AP diet for 7 days and then switched to diets containing soybean meal (AP-SBM) or AP-CM, while two other diets (SBM-AP and CM-AP) were started on one of the VP diets for 7 days and then switched to AP diet. A sub-experiment on thirty birds raised on a commercial diet to 7 days was used in a feed selection test to quantify the preference of birds for the diets containing mainly CM or SBM. Chicks were reared under similar care and management conditions and the diets were iso-caloric and iso-nitrogenous. Results of the main experiment showed that chicks on CM-AP diet ate more (p<0.05) than those on the other diets up to day 7. Body weight gain was highest (p<0.001) on the AP-SBM diet while birds on the CM-AP diet weighed the least at 7 d. Feed intake, body weight gain, feed conversion ratio, mortality, bone growth, visceral organ development, and activities of digestive enzymes were similar between the groups from hatch to 21 days of age. Results of the second sub-experiment showed that chicks preferred the CM-based diets to the SBM-based diets at 8 to 14 d (p<0.001) and 15 to 21 d (p<0.01) when given a choice. Overall, the birds were not affected by the nature of the starter diet although they tended to prefer the canola to soybean diets.

Evaluation of high dietary inclusion of distillers dried grains with solubles and supplementation of protease and xylanase in the diets of broiler chickens under necrotic enteritis challenge.

A 2 × 2 × 2 factorial experiment was conducted to investigate the effect of a high level of sorghum distillers dried grains with solubles (DDGS; 20%), with or without a combination of protease and xylanase in broiler chickens, under a necrotic enteritis disease challenge. A total of 576 male broiler chicks were randomly assigned to 8 experimental treatments, each replicated 6 times, with 12 birds per replicate for 35 d. Oral inoculation of the challenged group with Eimeria spp. occurred on d 9, followed by 3 consecutive inoculations of Clostridium perfringens from d 14 through 16. The disease challenge and DDGS inclusion significantly (P < 0.01) interacted, depressing BW gain and feed conversion ratio only in wk 3. Disease challenge adversely influenced (P < 0.01) BW gain and feed conversion ratio of the birds in the third week and across the 35-d study. Over the last 2 wk and across the 35-d trial, the interaction between DDGS and enzyme supplementation showed a tendency (P = 0.09) to gain more BW in birds regardless of the disease challenge. Inclusion of 20% DDGS markedly (P < 0.01) interacted with disease challenge, accelerating the proliferation of C. perfringens in the ceca at d 17. Inoculation of birds with C. perfringens resulted in higher (P < 0.01) counts of C. perfringens in both ileal and cecal contents. The necrotic enteritis-related lesions (d 17) were more severe (P < 0.05) in the intestine of infected birds fed DDGS diets than in birds fed the control diet. Incorporation of DDGS to the diets improved (P < 0.01) the IgA and IgG titer at d 13 but interacted with the disease challenge, reducing the concentration of IgA at d 21 and IgM at d 35 in the infected birds. In conclusion, incorporating a high level of DDGS in the diet of broiler chickens may increase susceptibility to necrotic enteritis. Supplementation of enzymes did not reveal significant mitigation effect in infected birds but helped the birds fed DDGS to maintain feed intake and BW gain.

The effect of insoluble fiber and intermittent feeding on gizzard development, gut motility, and performance of broiler chickens.

Two experiments were conducted to test the following hypothesis: exposing broiler chickens to coarse insoluble fiber in the diet will result in enhanced gizzard function and performance, improved adaptability to an intermittent feeding program, and an increase in the occurrence of reverse peristalsis. In experiment 1, 102 Ross 308 broiler chickens were either intermittently or ad libitum fed a basal diet, the basal diet diluted with 15% coarse hulls (consisting of equal weights of hulls from oats and barley), or the basal diet diluted with 15% of the same hulls finely ground in a 2 × 3 factorial arrangement with 17 individually caged birds per treatment. Birds fed ad libitum had access to feed continuously for 18 h/d, whereas those on intermittent feeding had restricted access to feed from 7 d of age. From 18 d of age, the restrictive-feeding program consisted of four 1-h meals and one 2-h meal per day. In experiment 2, 156 broiler chickens in 12 pen cages with wood shaving-lined floors were exposed to 1 of 4 treatment groups with 3 pens/treatment: intermittent or ad libitum feeding of a basal diet and intermittent or ad libitum feeding of a coarse hull diet, as described above. At 31 and 32 d of age, birds in experiment 1 were inoculated with chromium EDTA via the cloaca. There was no interaction between diet and feeding regimen. The addition of hulls increased gizzard weight and content and lowered (P < 0.001) gizzard pH, but it had no effect on the ability of the birds to handle intermittent feeding. Despite the dilution with coarse hulls, weight gain and the gain:feed ratio were not affected, which could partly be explained by an increased (P < 0.001) starch digestibility. Dietary reflux was confirmed by the presence of chromium in all intestinal tract sections. Broilers exhibited reverse peristaltic contractions of sufficient magnitude to propel the marker from the cloaca to the gizzard.

Trace mineral interactions in broiler chicken diets.

1. The aim of the present study was to demonstrate trace mineral interactions among organic copper, iron, manganese and zinc (Cu, Fe, Mn and Zn) in broiler chickens. 2. Three experiments were conducted using a control diet which was deficient in Cu, Fe, Mn and Zn. 3. In experiment 1, the control diet, supplemental organic Cu, Fe alone and combined diets, were randomly fed to 4 groups of one-day-old Cobb broilers (each group had 6 replicates of 4 birds). 4. In experiment 2, the control diet, supplemental organic Mn and Zn alone or combined with Cu, Fe diets and corresponding inorganic combined diet, were randomly fed to 6 groups (each group had 8 replicates of 6 birds). 5. In experiment 3, the depletion of organic Zn, the depletion of inorganic Zn and normal Zn treatments were carried out in three groups of one-day-old Cobb broilers (each group had 8 replicates of 6 birds). 6. Adding organic Cu, Fe and Mn alone or combined to Zn deficient diets did not significantly improve bird performance and were mostly excreted. Supplemental organic Zn alone or combined with other elements significantly increased feed intake, body weight gain and tibia bone length. However, supplemental organic Fe alone or combined with Cu significantly increased feed intake but had no obvious effect on body weight gain. The organic Fe supplementation resulted in a wider tibia. 7. Depletion of organic and inorganic Zn resulted in decreased feed intake, body weight gain and total tibia bone Zn content. Zinc deficiency did not affect the uptake of organic Fe by tibia bone but reduced its total Fe content. 8. Zinc is the first limiting element among these 4 trace minerals. Adding Mn, Cu and Fe to Zn deficient diets did not stimulate bird performance. Surplus organic Fe and Cu resulted in increased feed intake and increased tibia bone Fe content but did not contribute to bird performance.

Characterisation and response of intestinal microflora and mucins to manno-oligosaccharide and antibiotic supplementation in broiler chickens.

1. An experiment was conducted to characterise and evaluate, in comparison to zinc bacitracin (ZnB), the response of intestinal microflora and mucins to manno-oligosacchares (MOS, Bio-MOS(R), Alltech Biotechnology, Nicholasville, Kentucky, USA). 2. Supplementation of MOS and ZnB selectively increased the intensity of sulphomucins. As revealed by the plate culture method, MOS accelerated the maturation of gut microflora by promoting the growth of lactobacilli in the ileal mucosa and vice versa on ileal and caecal clostridia. Unlike MOS, ZnB suppressed the growth of intestinal bacteria, especially those of lactobacilli and clostridia. Use of T-RFLP further revealed that MOS increased the diversity of lactobacilli in the ileum and ileal mucosa but the opposite was observed for ZnB. It also appears that MOS and ZnB possessed a common property in differentially favouring the growth of certain Lactobacillus species. There was also evidence to show that both MOS and ZnB also increased the homogeneity of the gut microflora, possibly through the regulation of the overall gut bacterial communities. 3. Improvement in intestinal microbial homogeneity and mucin synthesis, coupled with the differential selections for certain specific beneficial bacterial species, may ultimately be proven to be the target mechanisms in the search for more effective alternatives to antibiotics.

Functional interactions of manno-oligosaccharides with dietary threonine in chicken gastrointestinal tract. I. Growth performance and mucin dynamics.

1. An experiment was conducted to evaluate the interactive effects of manno-oligosaccharides (MOS; Bio-MOS®) and dietary threonine on the growth performance in relation to intestinal mucin dynamics in broiler chickens from 1 to 21 and from 22 to 35 d of age. Two concentrations of MOS (0 or 2 g/kg for d 1 to 21; and 0 or 1 g/kg for d 22 to 35) and three concentrations of threonine (0.0, 1.0 and 1.2 of National Research Council (NRC), 1994, recommendations) were included in the experimental diets for each age group. 2. Body weight gain was significantly lower in threonine-deficient birds compared with those fed on adequate or excess threonine diets. Positive interaction between MOS and threonine supplementation on body weight gain was apparent in all phases of growth due mainly to the significantly poorer performance of birds given excess threonine in the absence of MOS. 3. The duodenal and ileal adherent mucous thickness were reduced at 14 and 28 d in threonine-deficient birds. Nevertheless, MOS significantly increase duodenal adherent mucous thickness at 14 d and ileal mucous thickness at 14 and 28 d. At 14 d, a significant MOS and threonine interaction on the jejunal adherent mucous thickness was also noted in that there was no difference between adequate and excess threonine groups in the absence of MOS, but a significant increase with excess threonine and MOS supplementation. 4. Dietary threonine greatly influenced mucin synthesis at the translational stage with no effect on jejunal MUC2 gene expression. Conversely, MOS modulated the transcriptional stage of intestinal mucin synthesis by consistently up-regulating jejunal MUC2 gene expression which was independent of dietary threonine concentration. There were no significant interactions between threonine and MOS on all the goblet cell densities. However, there was a MOS and threonine interaction on the staining intensities of jejunal sulphomucins due mainly to the significantly lower staining intensities in birds fed excess threonine in the absence of MOS. 5. The ameliorative effect of MOS on the growth-suppressive effects of excess threonine is likely to be linked to its modulating effects on the intestinal mucin dynamics.

Functional interactions of manno-oligosaccharides with dietary threonine in chicken gastrointestinal tract. III. Feed passage rate.

1. A 3 × 2 factorial experimental design was used to investigate the interaction between threonine concentration (0.70, 1.0 and 1.3 of National Research Council (NRC), 1994, recommendations) and manno-oligosaccharides (0 and 2 g/kg) on feed passage rate in relation to intestinal microbial activities and crude mucin turnover. 2. There was no interaction between the effects of manno-oligosaccharides (MOS) and dietary threonine on total tract transit time. However, an interaction between MOS and threonine was apparent where increasing threonine in the absence of MOS led to a reduction in the mean retention time, but a trend in the opposite direction in the presence of MOS. The ileal mean retention time at deficient and adequate concentrations of threonine was also significantly shorter in the presence of MOS. 3. In the jejunum, dietary MOS interacted with threonine to increase the villus-to-crypt ratio with deficient and adequate concentrations of threonine but not with an excess. In the ileum, MOS had no effect on the villus-to-crypt ratio at the deficient and adequate concentrations of threonine but significantly increased the ileal villus-to-crypt ratio with an excess. 4. There were significant interactions between MOS and dietary threonine in their effects on ileal flow of crude mucin, with MOS supplementation increasing mucin concentration and output when threonine was adequate but not when deficient or in excess. 5. Neither MOS nor threonine affected volatile fatty acids and intestinal musculature. No effects of gut microflora or voluntary feed intake on feed passage rate was attributable to dietary threonine or MOS supplementation.