Effects of star anise (Illicium verum Hook.f.), essential oil,and leavings on growth performance,serum, and liver antioxidant status of broiler chickens

An experiment using 384 one-day-old male Arbor Acres broilers that were randomly allocated to 4 treatments with 8 replicates in a completely randomized design was conducted to assess the effects of star anise (Illicium verum Hook.f.), essential oil, and leavings on growth performance and antioxidant status of broiler chickens. The treatments were corn-soybean meal based diets supplemented with 5 g/kg star anise, 0.2 g/kg essential oil, and 5 g/kg leavings of the diets for 42 days. All broilers had similar feed conversions over the entire experimental period. However, broilers supplemented with star anise and its essential oil had higher (P < 0.05) ADG and ADFI than those of the control and leavings. Supplementation of star anise and its essential oil increased (P < 0.05) activities of super dismutase, glutathione peroxidase, and catalase but decreased (P < 0.05) content of malondialdehyde in the serum of broilers at 21 d and 42 d of age. And it also increased (P < 0.05) activities of super dismutase and catalase but decreased (P < 0.05) concentrations of malondialdehyde in the liver of broilers at the same periods. Dietary supplementation of star anise and its essential oil improved growth performance and serum and liver antioxidant status. The efficacy is best at 5 g/kg star anise or 0.2 g/kg essential oil in the diet.     

Growth performance,economic benefits and sensory characteristics of meat from broilers finished on <Emphasis Type="Italic">Acacia anguistissima</Emphasis> leaf meal-based diets

The objective of the study was to determine growth performance, viscera organ development, economic benefit and sensory characteristics of meat from broilers finished on Acacia anguistissima leaf meal-based diets. One hundred and eighty Cobb 500-day-old chicks were used in the study. Acacia anguistissima was used as a protein source and included in broiler diets at 0, 50 and 100 g/kg. Total feed intake (TFI), average daily gain (ADG), and gain to feed ratio (G:F) and cost benefit analysis were determined. There were no differences in TFI of broilers across treatments diets. Average daily gain and gain to feed (G:F) ratio were low (P?<?0.05) for broilers feeding on diet with100 g/kg acacia meal. Highest returns from weight gain were obtained from broiler chickens fed on diet with 50 g/kg inclusion level of A. anguistissima (P?<?0.05). Intestinal length increased with inclusion level of A. anguistissima whereas liver and spleen weight decreased with inclusion level of A. anguistissima (P?<?0.05). Female consumers gave higher scores for overall flavour intensity than male consumers (P?<?0.05). Treatment diets influenced consumer sensory characteristics of broiler meat (P?<?0.05). High sensory scores were observed for overall flavour intensity (OFI) for both boiled and deep fried meat from broilers fed 100 g/kg A. anguistissima. It can be concluded that A. anguistissima meal can be used effectively up to 50 g/kg in broiler diets without compromising performance of chickens and can influence a few sensory characteristics.     

Effect of supplemental zinc source and corn particle size on 40-day broiler performance

Zinc (Zn) supplementation source and particle size of feed ingredients are two factors that can affect poultry performance and should be considered for proper feeding of poultry. The objective of the current study was to assess the effects of Zn supplementation source and corn particle size on broiler performance, breast yield, and tibia Zn concentration. Treatments were arranged in a 5 × 2 factorial randomized complete block design with the main effects Zn treatment and corn particle size (550 micron vs. 1,050 micron). Zinc treatments included a basal diet (no added Zn), 80 mg/kg Zn sulfate, and 3 diets with 40 mg/kg Zn sulfate + 40 mg/kg of either Zn-glycine amino acid (AA) chelate (Zn-gly), Zn-AA complex (Zn-AA), or Zn bis(-2-hydroxy-4-methylthio)butanoic acid (Zn-HMTBA). A total of 8 replications per treatment were fed to 23 broilers per pen from d one to 40. A Zn treatment x corn particle size interaction was observed for ending bird weight (EBW; P < 0.05) demonstrating that feeding small particle corn produced larger broilers except when supplemental Zn was not included. Broilers fed small particle corn or diets supplemented with Zn consumed the most feed (P < 0.05); however, FCR was decreased (P < 0.05) by 1.9 points for broilers fed large particle corn diets. Tibia Zn concentration was higher (P < 0.0001) for Zn supplemented diets, but no other treatment effects were observed. In conclusion, Zn supplement source had little effect on broiler performance; however, Zn supplementation per se optimized performance.     

Effects of supplementation of probiotics and prebiotics on growth performance,nutrient digestibility,organ weight,fecal microbiota,blood profile,and excreta noxious gas emissions in broilers

This experiment was conducted to investigate the effects of supplementation of probiotics and prebiotics on growth performance, nutrient digestibility, relative organ weight, fecal microbiota, blood profile, and excreta noxious gas emissions in broilers. A total of 714 one-day-old mixed sex ROSS 308 broilers with the initial BW = 40 ± 0.69 g was used in a 4-week trial. All birds were raised in wire cages. Birds were randomly allotted to 7 treatments with 6 replicates per treatment and 17 broilers per pen. Dietary treatments included: 1) T1 (control), 2) T2 [T1 + 0.2% probiotics (Bacillus sp. 1 × 10⁹ CFU, Lactobacillus sp. 1 × 10⁸ CFU, Aspergillus niger. 1 × 10⁷ CFU)], 3) T3 (T1 + 1% chicory fiber), 4) T4 (T1 + 1% rice bran), 5) T5 (T1+ 0.2% probiotics + 1% chicory fiber), 6) T6 (T1 + 0.2% probiotics + 1% rice bran), and 7) T7 (T1 + 0.2% probiotics + 1% chicory fiber + 1% rice bran). During d 1 to 14, broilers fed the T5, T6, and T7 diets had greater body weight gain (BWG) compared with the T1 diet (P < 0.05). Moreover, probiotics-included treatments resulted in higher BWG compared with the probiotics-free diets (P < 0.05). Broilers fed the T7 diet increased more in BWG compared with those fed the T1 diet, whereas feed conversion ratio (FCR) decreased more in the T7 diet than the T1 diet overall (P < 0.05). Dry matter (DM) digestibility increased more in the T5, T6, and T7 diets compared with the T1 diet (P < 0.05). Broilers fed probiotics-based diets had more improved DM digestibility compared with those fed probiotics-free diets (P < 0.05). Excreta Lactobacillus counts increased more in the T7 diet compared with the T1 diet (P < 0.05). Broilers fed with probiotics diets had higher excreta Lactobacillus counts compared with those fed the probiotics-free diets (P < 0.05). In conclusion, supplementation with 0.2% probiotics and 1% dietary fiber as prebiotics could improve the growth performance, DM digestibility, and excreta Lactobacillus counts in broilers raised in wire cages.     

Anise oil dosage and its effect on growth performance and jejunal lesions during a Clostridium perfringens challenge in battery trials,and growth performance in a floor pen trial,

Anise oil (AO) is a phytochemical with antibiotic properties and it reduces the growth of Clostridium perfringens in vitro, which is the main causal agent of necrotic enteritis. A series of battery experiments was conducted to determine an AO dosage to feed to broilers and its effect during 2 C. perfringens challenges, and a floor pen experiment to determine its effect in performance. Anise oil linearly reduced (P < 0.05) ADFI and ADG, but feeding broilers 500 to 2,000 mg/kg of AO resulted in similar performance with positive control (PC) fed broilers. Broilers were challenged on d 10 (Experiment 2) or on d 10 and 13 (Experiment 3). Broilers fed AO had lower (P < 0.05) ADFI and ADG compared with broilers fed PC from zero to 18 d (Experiment 2). Growth performance of broilers fed AO was not affected (P > 0.05) during Experiment 3. In both challenges, the jejunum of broilers fed AO had fewer and milder (P < 0.05) lesions compared with broilers fed PC or negative control (NC) diets. In a floor pen trial, 1,000 mg/kg of AO was fed to broilers from zero to 42 days. Broilers fed AO or PC had similar (P > 0.10) growth performance for the entire trial. Broilers fed PC or AO had greater ADG (P < 0.05) and tended (P = 0.07) to be heavier than broilers fed NC at the end of the trial. Breast yield percentage was similar (P > 0.10) among broilers fed any of the dietary treatments. Residues of AO were not present at detectable levels in breast meat.     

Effect of Spray-Dried Plasma Form and Duration of Feeding on Broiler Performance During Natural Necrotic Enteritis Exposure

The effect of duration of feeding (continuous or discontinued after d 14) and form (granular vs. powder) of spray-dried plasma (SDP) on performance and mortality of broilers using used litter was evaluated with 240 Ross × Ross 308 male broilers (6 broilers per pen, 8 pens per treatment). Dietary treatments were control (no SDP) or SDP as powder or granular included in the pellet and fed continuously (d 0 to 35) or discontinued after d 14. During the experiment, broilers developed necrotic enteritis, and tissue cultures were positive for Escherichia coli and Salmonella, resulting in 50% mortality on control broilers. Addition of SDP to the feed improved (P < 0.05) average daily gain, feed intake, and feed efficiency for each period of the study (d 0 to 14, 15 to 28, 29 to 35, and 0 to 35). Continuous feeding of SDP improved (P < 0.05) average daily gain, feed intake, and feed efficiency from d 15 to 35 compared with broilers fed SDP to d 14. Liveability was improved (P < 0.05) in broilers consuming SDP either for 14 d or continuously throughout the experiment compared with control broilers. Spray-dried granular plasma was more effective than spray-dried powder plasma from d 0 to 14. The results of this experiment confirmed that SDP improved broiler growth rate, feed intake, feed efficiency, and minimized enteric challenge associated with necrotic enteritis with maximal protection afforded by continuous feeding. The response to SDP was independent of age of the broiler.     

Growth performance,apparent nutrient digestibility,caecal fermentation,ileal morphology and caecal microflora of growing rabbits fed diets containing probiotics and prebiotics

Ninety eight male, mixed breed weaner rabbits were used in a 70 day feeding trial to study the performance, apparent nutrient digestibility, caecal fermentation, ileal morphology and caecal microflora of growing rabbits fed diets containing Prediococcus acidilactis (1×10¹⁰ cfu/g; 0.5 g/kg), Bacillus cereus (1×10⁹ cfu/g; 0.5 g/kg), mannan oligosaccharides (MOS; 1 g/kg), arabinoxylans oligosaccharides (AX; 1 g/kg), oxytetracycline (1 g/kg), or synbiotics (TGI; 1 g/kg). A basal diet containing no feed additive was formulated. There were 14 rabbits per treatment. Rabbits fed diets containing MOS had the highest (P<0.05) final live weight and weight gain. Dietary inclusion of prebiotics (MOS, AX) resulted in higher (P<0.05) weight gains and improved feed to gain ratios. Rabbits fed diets containing MOS showed the highest (P<0.05) while those fed diets containing probiotics (Prediococcus acidilactis, Bacillus cereus) had the least (P<0.05) caecal total volatile fatty acid (VFA) concentration. Rabbits fed diets containing prebiotics (MOS, AX) had longer ileal villi than groups fed with other treatments (P<0.05). Inclusion of various additives showed reduced caecal coliform counts. The lowest (P<0.05) lactobacillus count was obtained in the caecal content of rabbits fed diets containing MOS. Poor growth response was obtained with rabbits fed diets containing Prediococcus acidilactis or Bacillus cereus while inclusion of prebiotics in growing rabbits resulted in improved growth and gut morphology. Rabbits fed diet containing MOS showed the highest overall final live weight, weight gain, total VFA concentration and reduced caecal lactobacillus count.     

Combinatorial Effect of Dietary Oregano Extracts and 3,4,5-Trihydroxy Benzoic Acid on Growth Performance and Elimination of Coccidiosis in Broiler Chickens

We aimed to compare the combinatorial effect of 3,4,5-trihydroxybenzoic acid (THB) and oregano extracts (OE) with THB alone on the growth performance and elimination of deleterious effects in coccidiosis-infected broilers. A total of 210 one-day-old broilers were randomly assigned to one of five dietary treatments, with six replicates each, for 35 days. Dietary treatments were: 1) non-challenged, non-treated (NC); 2) challenged, non-treated (PC); 3) PC+ Salinomycin (0.05 g/kg; AB); 4) PC+THB (0.1 g/kg; THB); and 5) PC+THB+OE (0.1 g/kg; COM). On day 14, all groups except for NC were challenged with a 10-fold dose of Livacox^® T anticoccidial vaccine to induce mild coccidiosis. All treatments significantly improved (P<0.05) body weight, average daily gain, and average daily feed intake, compared to PC, on days 21, 28, and 35. However, all treatments significantly reduced (P<0.05) the feed conversion ratio of PC by more than 14.60% on day 35, 11.76% during growing period, and 10.36% through the entire period. Broilers receiving anticoccidial treatments had 54.23% and 51.86% lower lesion scores (P<0.05) at 4 and 7 days post-infection, respectively, compared to PC. Additionally, the villus height of COM was significantly longer (P < 0.05) than that of THB. Although the molecular action of COM remains unclear, OE addition to THB reduced the shedding of oocysts better than THB alone (P<0.05, 9-11 days post-infection). Most importantly, COM effectively minimized the mortality of challenged birds from as high as 11.90% (PC) to 0%, a level similar to NC and AB, while THB maintained a mortality of 2.38%. In conclusion, the anticoccidial effect of THB can be enhanced by the addition of OE for better animal performance and the elimination of deleterious effects from coccidiosis-infected broilers for 35 days.     

Effects of dietary supplementation of synbiotics on growth performance,intestinal morphology,sIgA content and antioxidant capacities of broilers

Today, several strategies are being used to decrease the serious effects of antibiotics abuse on broilers industry and public health, among which synbiotics are one of the most promising antibiotic alternative. This study was undertaken to assess the effects of synbiotics, which composed of probiotics (Bacillus subtilis) and prebiotics (xylooligosaccharide and mannanoligosaccharide), on growth performance, intestinal morphology, sIgA content and antioxidant parameters of broilers. Four hundred and fifty one‐day‐old commercial Cobb48 broilers were assigned to five treatments consisting of six replicates of 15 birds each pen. Five dietary treatments include basal diets (control), basal diets plus antibiotics (4 mg/kg Xanthomycin), basal diets plus 1 g of probiotics B. subtilis product/kg of diets (4 × 10⁸ cfu/kg), basal diets plus 150 mg/kg xylooligosaccharide (35%) and 1 g/kg mannanoligosaccharide (75%), and basal diets plus synbiotics (1 g of probiotics B. subtilis product/kg of diets (4 × 10⁸ cfu/kg), 150 mg/kg xylooligosaccharide (35%) and 1 g/kg mannanoligosaccharide (75%). The results demonstrated that on 21 and 42 days, dietary supplementation of the synbiotics significantly increased daily weight gain (p < 0.05), feed efficiency (p < 0.05), the villus height and villus:crypt ratio in the duodenum, jejunum and ileum (p < 0.05), as well as intestinal mucosa sIgA content (p < 0.05), serum T‐SOD activity (p < 0.05) and lysozyme content (p < 0.05), comparing with control group. In conclusion, synbiotics (B. subtilis and xylooligosaccharide and mannanoligosaccharide) is one of the safe and ideal dietary supplementations to increase broilers' growth performance by improving small intestinal morphology, sIgA content and antioxidant capabilities.     

Effects of dietary 1 alpha-hydroxycholecalciferol in calcium and phosphorous-deficient diets on growth performance,tibia related indices and immune responses in broiler chickens

This experiment was conducted to investigate the effect of dietary 1α-hydroxycholecalciferol (1α-OH-D₃) in calcium (Ca)- and phosphorous (P)-deficient diets on growth performance, carcass characteristics, tibia related parameters, and immune responses of broiler chickens. A total of 280 one-day-old broiler chickens (Ross 308) were assigned to 20 floor pens and 4 dietary treatments with 5 replicates. Dietary treatments consisted of starter diets (starter diet of treatment A: 1% Ca, 0.73% total phosphorus [tP]; starter diet of treatment B: 0.85% Ca, 0.64% tP + 5 μg/kg of 1α-OH-D₃; starter diet of treatment C: 0.85% Ca, 0.59% tP + 5 μg/kg of 1α-OH-D₃; starter diet of treatment D: 0.85% Ca, 0.54% tP + 5 μg/kg of 1α-OH-D₃), grower diets (grower diet of treatment A: 0.86% Ca, 0.68% tP; grower diet of treatment B: 0.73% Ca, 0.59% tP + 5 μg/kg of 1α-OH-D₃; grower diet of treatment C: 0.73% Ca, 0.55% tP + 5 μg/kg of 1α-OH-D₃; grower diet of treatment D: 0.73% Ca, 0.50% tP + 5 μg/kg of 1α-OH-D₃) and finisher diets (finisher diet of treatment A: 0.81% Ca, 0.64% tP; finisher diet of treatment B: 0.68% Ca, 0.56% tP + 5 μg/kg of 1α-OH-D₃; finisher diet of treatment C: 0.68% Ca, 0.52% tP + 5 μg/kg of 1α-OH-D₃; finisher diet of treatment D: 0.68% Ca, 0.48% tP + 5 μg/kg of 1α-OH-D₃). Results showed that body weight gain (BWG) and feed intake (FI) of broilers in treatment B were similar to those of broilers in treatment A at the end of the trial (P < 0.05). Broilers in treatments C and D had lower BWG and FI than those in treatment A during the whole trial (P < 0.05). Feed conversion ratio, carcass traits and relative weight of lymphoid organs were not affected by dietary treatments (P > 0.05). Dietary treatments had no significant effect on antibody titers against Newcastle and Influenza disease viruses as well as sheep red blood cells. Dietary treatments had no significant effects on tibia ash and tibial dyschondroplasia score. Broilers fed Ca-P deficient diets had lower tibia Ca and P than those in treatment A (P < 0.05). In conclusion, results indicated that broilers fed Ca-P deficient diets supplemented with 5 μg/kg 1α-OH-D₃ failed to achieve the same tibia Ca and P values as broilers fed nonphytate phosphorus adequate diets.     

Assessment of interactions between glutamine and glucose on meat quality,AMPK, and glutamine concentrations in pectoralis major meat of broilers under acute heat stress

The objective of this experiment was to evaluate the effects of dietary glutamine and glucose on pectoralis major meat quality in broilers under acute heat stress. Three hundred 35-day-old male broilers (Arbor Acres) were randomly divided into 5 groups. Broilers in the positive control group were kept in a thermoneutral environment (23 ± 1°C, RH 45%–55%) and fed a basic diet, whereas the experimental (2 × 2) group was exposed to acute heat stress (34 ± 1°C, RH 65%–75%) for 12 h and fed the basic diet that contained glutamine (0 and 10 g/kg) and glucose (0 and 10 g/kg). Compared with the positive control group, acute heat stress without glutamine and glucose supplementation increased (P < 0.05) drip loss, L* values, and AMPK concentrations, but it decreased (P < 0.05) water-holding capacity, moisture, pH, a* values, b* values, and glutamine concentrations in pectoralis major meat of chickens. However, dietary glutamine (10 g/kg) increased (P < 0.05) water-holding capacity, moisture, pH, a* values, b* values, and glutamine concentrations, while it decreased (P < 0.05) drip loss, L* values, and AMPK concentrations in heat-stressed chicken pectoralis major meat. Dietary glucose (10 g/kg) increased (P < 0.05) water-holding capacity, moisture, pH, and a* and b* values, while it decreased (P < 0.05) L* values and AMPK concentrations of pectoralis major meat in chickens exposed to acute high temperature. There were significant interactions between glutamine and glucose in the water-holding capacity, pH values, AMPK, and glutamine levels of pectoralis major meat in the heat-stressed chickens. The above results suggest that the addition of glutamine and glucose in the diet is necessary for broilers during acute heat stress condition.     

Direct-fed microbial and its combination with xylanase,amylase, and protease enzymes in comparison with AGPs on broiler growth performance and foot-pad lesion development

This study evaluated the effect of a direct-fed microbial (DFM) and its combination with xylanase, amylase, and protease (XAP) enzymes cocktail on performance of broilers, in comparison with two commonly used antimicrobial growth promoters (AGPs). Five treatments were tested using day-old Ross 708 broilers (mixed sex at 50:50 ratio) in a completely randomized design with 8 replications per treatment (40 birds/pen) using built up litter. Treatments were 1) a negative control (NC) based on corn/soy/wheat (10%) containing 500FTU/kg phytase, 2) NC + DFM (150,000 CFU/g of 3 Bacillus strains) (DFM150); 3) NC+ DFM (75,000 CFU/g of 3 Bacillus strains) in combination with XAP, XAP + DFM75); 4) NC+ BMD (50 g/ton), and 5) NC+ virginiamycin (20 g/ton). Diets were fed in mash form ad libitum in 3 phases: d 1 to 10 (starter); d 11 to 21 (grower) and d 22 to 42 (finisher). Body weight and feed intake (FI) were measured per phase and feed conversion ratio (FCR) was corrected for mortality weight. Treatment means were compared using a one-way analysis of variance (ANOVA) and separated via Duncan's Multiple Range Test. Supplementation of DFM increased (P < 0.05) average BW at d 10 when compared to the NC. Overall 42-d data indicated that the combination of XAP+DFM75 reduced (P < 0.05) mortality weight corrected FCR compared to NC, both DFM150 and the combination of XAP+DFM75 did not differ from both AGP treatments. Feed intake and body weight gain (BWG) were not affected by treatments during the 42-d study. The combination of XAP+DFM75 also reduced (P < 0.05) foot-pad lesion score as well as improved energy efficiency compared to the NC. These data indicate that both DFM150 and the combination of XAP + DFM75 may be used as an alternative to AGPs to achieve similar growth performance when producing broilers chickens under similar conditions.     

Dietary organic acid and fiber sources affect performance,intestinal morphology,immune responses and gut microflora in broilers

This experiment was designed to investigate the effects of a dietary organic acid (OA) mixture and 2 fiber sources on performance, intestinal morphology, immune responses and gut microflora in broilers. A total of 390 one-day-old broiler chicks (Ross 308) were allocated to 6 dietary treatments with 5 replicate pens and 13 chicks each based on a factorial arrangement (2 × 3) in a completely randomized design. The experiment lasted 42 d. The following experimental diets and as well as their interaction were considered: a basal diet supplemented with or without OA (0 or 1 g/kg) and 2 fiber sources (sugar beet pulp [soluble fiber] or rice hull [insoluble fiber]; 0 or 30 g/kg). Dietary supplementation of OA increased daily weight gains of broilers across the entire rearing period (P < 0.05). The dietary fibrous materials did not affect the performance of broilers. Antibody titer against influenza disease virus was higher in birds fed diets containing rice hull compared with other experimental groups (P < 0.05). The population of Lactobacillus bacteria was greater in birds fed OA-added diets without or with 30 g/kg rice hull supplementation compared with other experimental groups (P < 0.05). In conclusion, dietary supplemental OA improved performance of broilers, and dietary supplemental OA with rice hull enhanced humoral immune responses.     

Effects of Early Feed Restriction on Performance and Ascites Development in Broiler Chickens Subsequently Raised at Low Ambient Temperature

The objective of this study was to examine the effectiveness of early-age growth limitation, achieved through feed restriction (FR), as a means of reducing ascites mortality in broiler chickens exposed to low ambient temperatures. Feed restriction was applied to broilers from 5 to 11 d of age so as to reduce their weight gain to about 40% of that of control broilers that were fed ad libitum (AL). At the age of 21 d the chickens were exposed to a temperature of 15°C, which induced ascites. By 46 d of age, ascites incidence and mortality in the feed-restricted birds were reduced to 15.79 vs. 36.84% and 7.89 vs. 26.32%, respectively, compared with those in the controls (P < 0.05). After feed restriction was stopped, the FR chickens had accelerated weight gain and improved feed conversion ratio from 11 to 18 d of age (P < 0.05), and by 46 d they had achieved the same body weight as the AL birds. Ascitic broilers had smaller relative breast muscle and spleen weights than those of the healthy broilers at 46 d (P < 0.05). However, the relative weights of lung, heart, and liver and the right ventricle weight per total ventricle weight (RV:TV) ratios were greater in ascitic broilers (P < 0.05). At age 37 d, when ascites had developed but not yet caused mortality, the ascitic broilers had lower plasma concentrations of the thyroid hormones thyroxine and triiodothyronine, and higher hematocrit values (P < 0.05) in comparison with the healthy ones. Ascitic birds also had lower oxygen consumption at 6 wk (P < 0.05), which agrees with information that the terminal stage of the ascites syndrome can be characterized by low oxygen consumption. We concluded that the early-age feed restriction reduced ascites incidence and mortality and prevented reduction of the thyroid hormone concentrations in male broilers reared at low ambient temperature from the age of 3 wk onward.     

Effects of Increasing Stocking Density on the Performance and Ileal Microbiota of Broilers

This study was conducted to investigate the effects of increasing stocking density under suitable environmental conditions on the performance and ileal microbiota of broilers. A total of 108 Arbor Acres male broilers (28 days old) were allocated to a normal stocking density (NSD, normal stocking density; 31 kg/m²) and a maximum allowed stocking density group (MSD, maximum stocking density; 39 kg/m²). All birds were reared at a constant temperature of 21°C. At 42 days of age, bacterial DNA was extracted from ileal content, and the V3–4 hypervariable region of 16S rRNA was amplified. Increasing stocking density had no significant effect on average daily gain, average daily feed intake, and feed conversion ratio (P>0.05). The alpha and beta diversities of the ileal microbiomes did not differ significantly between the NSD and MSD groups; however, increasing stocking density altered the composition of ileal microbiota. The relative abundance of Lactobacillales, including Lactobacillus, Enterococcus, and Streptococcus, significantly decreased in MSD broilers, compared with NSD broilers. The present results suggest that even under suitable environmental conditions, an increase in stocking density to a level of 39 kg/m² may disturb the composition of ileal microbiota in broilers. Further studies are needed to determine the reasons and the potential consequences for animal health and physiology.     

Dietary supplementation with acidifiers improves the growth performance,meat quality and intestinal health of broiler chickens

This experiment was conducted to study the effects of dietary supplementation with acidifiers on the growth performance, meat quality, and intestinal health of broiler chickens. A total of 648 male Arbor Acres broiler chickens at 1 d old were randomly divided into 6 groups, and each group consisted of 6 replicates with 18 broilers per replicate. The dietary treatments were as follows: negative control (NC, the basal diet), NC + antibiotic (enramycin, 8 mg/kg, positive control [PC]), NC + phosphoric acid (PA, 0.1, 0.2, and 0.3 g/kg), and NC + lactic acid (LA, 0.3 g/kg). The feeding trial lasted for 42 d. The results showed that the feed-to-gain ratio of the NC + acidifier groups was lower than that of the NC and PC groups from 1 to 42 d (P < 0.05). Compared with the values in the NC group, the pH of breast muscle was significantly higher in the NC + PA (0.2 g/kg) and LA (0.3 g/kg) groups (P < 0.05), and the cooking loss was lower in the breast muscle of the NC + PA (0.1 g/kg) and LA (0.3 g/kg) groups (P < 0.05). In addition, the shear force of the breast muscle and thigh muscle and the pH value in the crop, gizzard and duodenum of the antibiotic and acidifier groups were significantly decreased (P < 0.05). Moreover, the trypsin, chymotrypsin, and lipase activities of the duodenum in the NC + PA (0.2 and 0.3 g/kg) groups, as well as the villus height-to-crypt depth (VH:CD) ratio of the duodenum in the NC + PA (0.1 g/kg) group was significantly greater (P < 0.05) compared with those in the NC group. Meanwhile, the number of total aerobic bacteria, Escherichia coli and Salmonella in the cecum of the NC + PA (0.1 g/kg) and LA (0.3 g/kg) groups were decreased (P < 0.05). Collectively, diet supplementation with acidifiers could improve the growth performance, meat quality, and intestinal health of broilers, in which the effects of PA (0.1 g/kg and 0.2 g/kg) are better than the other supplementations.     

Influence of fibre and betaine on development of the gastrointestinal tract of broilers between hatch and 14 d of age

An experiment was designed to determine the influence of fibre and betaine on the development of the intestine, liver and pancreas of broilers from hatch to 14 d of age. A total of 250-day-old Cobb 500 male broilers were allocated to 16 cages with 15 broilers each. Treatments were arranged in a 2 × 4 factorial design, consisting of 2 feed formulations (low and high fibre diets) and 4 levels of betaine (0, 1, 3 or 5 kg/t). At hatch, 10 birds in total were euthanised, and samples of the liver, pancreas, yolk sac and intestine were collected for reference of the analysed parameters before the start of the trial. On d 4, 9 and 14, 5 birds per cage (10 birds per treatment) were selected, euthanised and treated as the same as the birds at hatch. Villus height and width and crypt depth were determined on the duodenum samples, and absorptive area was calculated. The number of enterocytes in mitosis at the villus was determined by a positive reaction to antibody for Ki67 protein, and fused villus was evaluated visually. The relative weight of the yolk sac reduced (P < 0.05) as birds aged while the intestine and liver reached a maximum (P < 0.05) at around d 4 and the pancreas at d 9. Birds fed the high fibre diet had greater feed intake, lower relative weight of the pancreas and higher villus (P < 0.05) than birds fed the low fibre diet. Villus width increased (P < 0.05) at 4 d of age, and this was associated with fused villus. Betaine inclusion reduced (P < 0.05) villus width, increased (P < 0.05) villus size and absorptive area, and reduced (P < 0.05) the number of enterocytes with positive reaction for the antibody Ki-67. Betaine inclusion reduced the width and increased the absorptive area and the villus height of the duodenum of birds up to 14 d of age. The higher fibre diet increased feed intake and villus height, yet reduced pancreas relative weight, while not affecting body weight gain. This response was possibly due to a dilution effect of the fibre, reducing nutrient absorption and consequently stimulating villus growth to improve absorption rates.     

Evaluation of a thermotolerant xylanase on broiler growth performance and dietary ileal digestible energy value

Two experiments were conducted to evaluate the impact of a thermotolerant xylanase on male broiler performance and dietary ileal digestible energy (IDE). The first experiment consisted of 3 treatment groups with 12 replications per treatment each containing 35 Cobb 500 males for a total of 1,260 broilers placed in floor pens for a 42 d grow-out. The experiment treatments included a corn/soy diet with DDGS control formulated at a low energy level, and the control supplemented with one of 2 concentrations of xylanase (20,000 XU/kg [XYL20] and 40,000 XU/kg [XYL40]). No significant differences in body weight were observed with the inclusion of xylanase when compared to the control diet throughout the experiment. At d 28, the inclusion of XYL20 improved (P < 0.05) mortality corrected feed conversion ratio (FCR) compared to the control diet. Feed conversion ratio was also improved (P < 0.01) at d 42 for birds fed XYL20 when compared to the control. At d 42, inclusion of XYL20 and XYL40 significantly (P < 0.05) increased IDE compared to the control. Experiment 2 consisted of 4 treatment groups with 10 replications per treatment each containing 44 Cobb 500 males for a total of 1,760 broilers placed in floor pens for a 41 d grow-out. The dietary treatments included a positive control (PC) based on a corn/soy diet containing DDGS and phytase, a negative control (NC) diet (PC -150 kcal/kg in AME), NC + xylanase at 10,000 XU/kg (XYL10), and NC + xylanase at 20,000 XU/kg (XYL20). A significant increase (P < 0.05) in BW was observed in broilers fed the inclusion of XYL20 in the NC diet increased (P < 0.05) on d 14. A significant increase in cumulative body weight gain was observed on d 27 and d 41 with xylanase (XYL20) inclusion compared to the NC. These data demonstrate that xylanase inclusion increased energy utilization through improvements in IDE, which improved broiler performance.     

Exogenous phytase and xylanase exhibit opposing effects on real-time gizzard pH in broiler chickens

ABSTRACT

1. The current study was conducted to evaluate the influence of high phytase doses and xylanase, individually and in combination, on performance, blood inositol and real-time gastric pH in broilers fed wheat-based diets.

2. In a 42-d experiment, a total of 576 male Ross 308 broiler chicks were allocated to 4 dietary treatments. Treatments consisted of a 2 × 2 factorial arrangement, with 500 or 2500 FTU/kg phytase and 0 or 16 000 BXU/kg xylanase, fed in two phases (starter 0–21; grower 21–42 d). Heidelberg pH capsules were administered to 8 birds from each treatment group, pre- and post-diet phase change, with readings captured over a 5.5-h period.

3. At 21 and 42 d, birds fed 500 FTU/kg phytase without xylanase had on average 127 and 223 g lower weight gain than all other treatments, respectively (P < 0.05). At 42 d, body weight-corrected feed conversion ratio (_bwcFCR) was reduced (P < 0.05) by supplementing 2500 FTU/kg phytase or xylanase, with the combination giving a 12 point reduction in _bwcFCR compared to birds fed 500 FTU/kg phytase without xylanase. Inositol content of plasma was twice that of the erythrocyte (P < 0.001), with 2500 FTU/kg phytase tending to increase (P = 0.07) inositol content in both blood fractions.

4. Across all treatments, capsule readings ranged from pH 0.54 to 4.84 in the gizzard of broilers. Addition of 2500 FTU/kg phytase to the grower diet reduced (P < 0.05) average gizzard pH from 2.89 to 1.69, whilst feeding xylanase increased (P < 0.001) gizzard pH from 2.04 to 2.40. In contrast, digital probe measurements showed no effect of xylanase on gizzard pH, while addition of 2500 FTU/kg phytase increased (P = 0.05) pH compared to 500 FTU/kg phytase with or without xylanase.

5. These findings suggested that xylanase and high phytase doses have opposite effects on real-time gastric pH, while similarly improving performance of broilers.     

Effects of periodical application of bioactive peptides derived from cottonseed on performance,immunity, total antioxidant activity of serum and intestinal development of broilers

This experiment aimed to examine the effect of periodical application of bioactive peptides derived from cottonseed (BPC) in comparison with using sub-therapeutic doses of lincomycin and the excessive inclusion of vitamin E on performance, immunity, total antioxidant capacity of serum and intestinal morphology of broiler chickens. A total of 240 one-d-old male broiler chicks with similar initial weight (Ross strain) were randomly assigned to 6 groups (8 chicks/pen): non-treated group (basal diet), basal diet supplemented with 2 mg/kg lincomycin, basal diet supplemented with 50 IU vitamin E, basal diet supplemented with 6 g BPC/kg in starter period, basal diet supplemented with 6 g BPC/kg in starter and grower periods and basal diet supplemented with 6 g BPC/kg throughout the whole experiment. The highest final body weight was obtained in the group supplemented with BPC in starter and grower periods. In the finisher phase, broilers fed the diet containing BPC in the starter period and in the whole trial had significantly (P < 0.05) better feed conversion ratios (FCR). Jejunal villus height was significantly elevated in broilers supplemented with antibiotic (P < 0.001), furthermore it tended to be greater in broilers fed BPC in the starter period. The jejunal villus height-to-crypt depth ratio was significantly (P < 0.01) higher in broilers fed the diet containing antibiotic in comparison to other groups. Humoral immune response against Newcastle disease vaccine tended to be elevated in broilers fed the diet containing BPC in the whole trial (P > 0.05). Broilers supplemented with BPC in starter and grower, and in the whole trial had significantly (P < 0.05) higher antibody titers against sheep red blood cells (SRBC). The highest total antioxidant capacity was obtained in broilers supplemented with the excessive level of vitamin E, furthermore it tended to improve in broilers fed the diet containing BPC in the whole trial. In summary, the results of the study indicated that addition of BPC in broiler diets in the whole trial could improve FCR, immune responses and total antioxidant activity of serum, and BPC could be used in broiler diets as an alternative to in-feed antibiotics.