Evaluation of Aloe vera and synbiotic as antibiotic growth promoter substitutions on performance,gut morphology,immune responses and blood constitutes of broiler chickens

This study was performed to investigate the effect of dietary supplementation with Aloe vera (AV) powder and synbiotic as growth promoter agents on performance, gut morphology, immune responses, hematology and serum biochemistry in broilers. A total of 240‐day‐old male broiler chicks (Ross 308) were randomly assigned to six treatments with four replicates. Birds were offered either a corn‐soybean meal basal diet (control) or the basal diet supplemented with 200 mg/kg virginiamycin (VM), 1 g/kg synbiotic (Syn), 2.5 g/kg AV (AV1), 5.0 g/kg AV (AV2) or 7.5 g/kg AV (AV3). Chickens fed any of the diets, except diet AV1, exhibited better feed conversion ratios at the 14–28 day period and higher average daily gain and duodenal villus height/crypt depth ratio at 42 days than those fed the control diet. Synbiotic supplementation caused a marked increase in the serum antibody titer against infectious bursal disease and infectious bronchitis vaccines. Feeding diet AV3 significantly increased red blood cell count and hemoglobin concentration, and decreased serum triglyceride level compared to the control group. The results suggested that dietary inclusion of 5 and 7.5 g/kg AV, similar with synbiotic supplementation, can be applied as effective alternatives to in‐feed antibiotics for broiler diets.     

Effects of a blend of thyme,peppermint and eucalyptus essential oils on growth performance,serum lipid and hepatic enzyme indices,immune response and ileal morphology and microflora in broilers

This study was conducted to evaluate the effect of a blend of essential oils (EOB) derived from thyme (Thymus vulgaris), peppermint (Mentha piperita) and eucalyptus (Eucalyptus globules) as a natural growth promoter. Five dosages (0 (CON), 50, 100, 150 and 200 ppm) of EOB were added daily to the drinking water to determine its effect on growth performance, carcass quality, blood biochemistry, immune response and ileal morphology in Ross 308 broiler chicks. A total of 500, 10‐day‐old male Ross 308 broilers were allocated into five treatments with four replicates each. Inclusion of EOB at 150 ppm improved (p < 0.05) body weight gain, feed conversion ratio and production index by 11.73, 10.81 and 24.13% compared to CON respectively. The inclusion of EOB at 100, 150 and 200 ppm increased (p < 0.05) carcass yield and thigh muscle compared to CON. Serum concentration of hepatic enzymes (alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase) was decreased while the ileal villus height and ratio of villus height to crypt depth were improved (p < 0.05) in response to inclusion of 150 and 200 ppm of EOB compared to CON. The ileal Escherichia coli count was lower and Lactobacillus count was higher in EOB‐200 and EOB‐150, respectively, compared to CON at 21 and 42 days of age (p < 0.05). Antibody titre of Newcastle, bronchitis and infectious bursal disease was linearly increased (p < 0.05) by increasing supplemental level of EOB at day 4 post‐inoculation. Our results suggested that supplementation of EOB at the 150 ppm into drinking water during day 11–42 could improve growth performance, humoral immunity and ileal morphology and microflora in broilers, and thus, EOB has merit to be used as an alternative to antibiotic growth promoters.     

Dietary supplementation of phenyllactic acid on growth performance,immune response,cecal microbial population,and meat quality attributes of broiler chickens

A total of 750 one-day-old male broiler chicks were randomly fed 5 dietary treatments with 5 replicate pens per treatment. The 5 dietary treatments fed for 42 d were a corn-soybean meal basal diet without antibiotic (control); a mixture of 10 ppm of avilamycin + 60 ppm of salinomycin as antibiotic growth promoters (AGP); 0.1% phenyllactic acid (PLA); 0.2% PLA; and 0.4% PLA. The BW gain and FE were significantly improved in AGP and PLA groups compared with control group. The white blood cells and heterophil counts were significantly higher in the PLA-supplemented groups compared with AGP and control groups, but the heterophil-to-lymphocyte ratio was lower in the control group than other groups. The plasma IgY concentration was significantly increased in birds fed PLA-supplemented diets, but the plasma IgA and IgM concentrations were not different among the treatment groups. In addition, the antibody titer against Newcastle disease virus was significantly higher in PLA-treated compared with control and AGP-treated groups. Neither PLA nor AGP treatments affected the cecal aerobes andSalmonella content; however, cecalLactobacillus population increased in chickens fed 0.1% PLA, and total coliform bacteria population significantly decreased in chickens fed various levels of PLA and AGP. Dietary supplementation of PLA did not affect the pH, lightness, and redness of breast meat, but the water-holding capacity and shear force value increased and the yellowness decreased significantly when birds were fed PLA. It was concluded that dietary supplementation of 0.1 and 0.2% PLA improves BW gain and FE of broiler chickens. In addition, PLA supplementation increases the immune characteristics and the number of lactic acid bacteria, decreases the number of coliform bacteria, and improves the meat quality attributes of broiler chickens. Thus, dietary PLA could be a viable alternative to antibiotics in broiler diets.     

Effect of dietary saponin rich soapnut (Sapindus mukorossi) shell powder on growth performance,immunity, serum biochemistry and gut health of broiler chickens

This study was conducted to evaluate the effects of dietary soapnut (Sapindus mukorossi) shell powder (SSP), a cheap source of saponins, on growth performance, immunity, serum biochemistry and gut health of broiler chickens. The experimental design was 4×2, employing four saponin levels (0, 100, 150 and 200 mg/kg diet), each provided for two time durations (0–42 day and 21–42 day) resulting into eight dietary treatments. Results revealed no significant effect of dietary saponins on body weight gain, feed intake and feed conversion ratio of birds. The abdominal fat percentage, heterophil to lymphocyte ratio, serum cholesterol and triglyceride levels, faecal total plate count, coliform count and E. coli count decreased (p < .05) progressively with increasing saponin levels and lower values were observed at 150 mg and 200 mg saponin levels. Significant improvement of cell‐mediated and humoral immune response was observed in birds fed 150 mg and 200 mg saponin compared to control. The serum glucose concentration was significantly (p < .05) higher in control group compared to other groups. No significant effects of dietary saponin were observed on carcass characteristics, faecal Lactobacillus count, intestinal histomorphometry and cost economics of broiler chicken production. Thus, dietary saponins at 150 mg/kg diet as SSP for three weeks (21–42 days) was optimum for better immunity and welfare of birds without adverse effects on the growth performance.     

Effect of herbal feed additives on performance parameters,intestinal microbiota,intestinal morphology and meat lipid oxidation of broiler chickens

ABSTRACT

1. This feeding trial investigated the effects of herbal feed additives on performance of broiler chickens, jejunal and caecal microbiota, jejunal morphology, meat chemical composition and oxidative stability during refrigerated storage.

2. In a 42 days trial, 320 one-day-old broiler chickens were randomly allocated to 4 groups with 4 replicate pens each containing 20 chicks. The control group was fed maize–soybean-based diets. The diets of the other three groups were supplemented with herbal feed additives: HRB1 with Stresomix^TM (0.5 g/kg feed); HRB2 with Ayucee^TM (1.0 g/kg feed); HRB3 with Salcochek Pro^TM (1.0 g/kg feed). The GC/MS analysis of the feed additives showed that the major components of HRB1 were β-caryophyllene (14.4%) and menthol (9.8%); HRB2 were n-hexadecanoic acid (14.22%) and β-caryophyllene (14.4%); and HRB3 were menthol (69.6%) and clavicol methyl ether (13.9%).

3. Intestinal samples were taken at 42 day to determine bacterial populations (total aerobe counts, Lactobacilli, and Escherichia coli) and perform gut morphology analysis. Meat samples were analysed for chemical composition and oxidative stability under storage.

4. The HRB1 group had improved (P < 0.05) body weight gain and tended to have improved (0.05 ≤ P < 0.10) feed conversion ratio, compared to the control group. Jejunum lactic acid bacteria counts were increased (P < 0.001) in groups HRB1 and HRB3, compared to the control group, whereas caecal lactic acid bacteria counts tended to increase (0.05 ≤ P < 0.10) in group HRB1, compared to the control group. Breast meat fat content tended to be lower (0.05 ≤ P < 0.10) in group HRB1. Meat oxidative stability was improved (P < 0.001), and jejunum villus height, crypt depth and goblet cells numbers were increased (P < 0.001) in all three herbal supplemented groups, compared to the control.

5. In conclusion, herbal feed additives may be able to improve both growth performance and antioxidant activity of broiler chickens, based on their phenolic compound content.     

Effects of dietary supplementation with a chlorella by‐product on the growth performance,immune response,intestinal microflora and intestinal mucosal morphology in broiler chickens

This study aimed to determine the effect of different dietary levels of a Chlorella by‐product (CBP) on the growth performance, immune response, intestinal microflora and intestinal mucosal morphology of broilers. In total, 480 one‐day‐old broiler chickens were randomly allotted to four dietary treatments with four replicated pens consisting of 30 chicks. The basal diet was formulated to be adequate in energy and nutrients. Three additional diets were prepared by supplementing 25, 50 or 75 g/kg of CBP to the basal diet. The diets were fed to the broilers ad libitum for 35 days. Result indicated that increasing inclusion level of CBP improved BW gain (linear, p < 0.05). There was no effect of inclusion level of CBP in diets on total cholesterol, triglyceride, aspartate aminotransferase and alanine aminotransferase levels during the 35 days. Plasma IgG, IgM and IgA concentrations increased (linear, p < 0.05) with inclusion level of CBP in diets. Supplementation of CBP in the diets increased (linear, p < 0.05) the concentrations of Lactobacillus in the caecal content and decreased (linear, p < 0.05) the concentrations of Escherichia coli and Salmonella in the caecal content. Villus height increased (linear and quadratic, p < 0.05) with inclusion level of CBP in diets. Crypt depth increased (quadratic, p < 0.05) with inclusion level of CBP, and a decreased villus height: crypt depth ratio (quadratic, p < 0.05) was observed as inclusion level of CBP in diets increased. The results of the current experiment indicate that dietary supplementation of CBP improves growth performance of birds. Dietary CBP has improving Lactobacillus spp. concentrations in the gastrointestinal tract, plasma immunoglobulin concentrations and intestinal mucosal morphology.     

日粮中添加蛋白酶对断奶仔猪生长性能、肠道形态和消化酶的影响

为研究日粮中添加蛋白酶对断奶仔猪生长性能、肠道形态和消化酶活性的影响,试验采用单因子完全随机试验设计,将50头28日龄断奶仔猪随机分为两组,对照组饲喂基础日粮,试验组在基础日粮中添加0.1%复合蛋白酶制剂。结果表明:与对照组相比,试验组断奶仔猪的平均日增重提高5.1%,料重比降低4.67%;试验组空肠的绒毛高度(VH)显著提高40.66μm(P<0.05),且绒毛隐窝比值提高了9.94%(P<0.05);试验组空肠的蛋白酶活性、淀粉酶活性均极显著升高,分别提高了2.89U/mL和23.25U/mL(P<0.01)。综上所述,在饲料中添加蛋白酶明显提高了仔猪的日增重,降低了料重比和成本,且促进了肠道绒毛和隐窝结构的发育和肠道消化酶的活性,改善了仔猪的生长性能。     

复合非淀粉多糖酶制剂对肉鸡生长性能及肠道酶活性的影响

将200只21日龄罗斯肉鸡分成5个处理组:处理1组(正对照组)、处理2组(负对照组),处理3～5组在负对照组日粮基础上各添加一种商业复合非淀粉多糖酶制剂产品。测定肉鸡生长性能及42日龄肠道消化酶活性。结果显示:处理3组肉鸡的料肉比显著优于(P≤0.05)处理1、2和5组;末体重指标,处理3和4组间无显著差异(P>0.05),但显著高于处理2和5组。处理3组肉鸡十二指肠的淀粉酶以及十二指肠内容物的蛋白酶活性显著高于(P≤0.05)处理1和2组。处理4和5组肉鸡的十二指肠淀粉酶和蛋白酶活性差异不显著,但显著低于处理3组。处理3组肉鸡空肠内容物的淀粉酶、蛋白酶和脂肪酶活性显著高于其它4个处理组。以上结果说明,选用复合NSP酶制剂应实测产品的酶种类和酶活性,以合理有效使用。     

Effect of organic acids or probiotics alone or in combination on growth performance,nutrient digestibility,enzyme activities,intestinal morphology and gut microflora in broiler chickens

A feeding trial was conducted to determine the effect of organic acids or probiotics alone or in combination on growth performance, nutrient digestibility, enzyme activity, intestinal morphology and gut microflora in broiler chickens (Ross308). A completely randomized design was used, with 1,440 broiler chicks across four treatments and five replications of 72 chicks each. The chicks in the control treatment were fed on a control diet (CD), whereas for the other treatment groups, the CD was supplemented with 0.2 g/kg organic acids (CDOA), probiotics (CDP) or a combination of organic acids and probiotics (CDOAP). All the chicks were fed ad libitum during the feeding trial throughout 35 days. A total of 20 chicks were randomly allotted to individual metabolic cages to measure the nutrient digestibility (35–42 days) and the digestive enzyme activities (42 days). The intestinal morphology and gut microflora of 80 chicks were examined at the end of experiment. There were no significant (p > .05) differences in the feed intake, body weight gain or feed conversion ratio of the chicks across the four dietary treatments. The crude fibre digestibility was significantly increased in chicks fed on CDOA or CDOAP relative to CD (p < .05). Nutrient utilization, in terms of digestive enzyme activities and excreta thermal property, was unchanged by any supplementation. The chicks fed on the CDOAP had significantly higher duodenal villi height and crypt depth than the chicks fed on CDOA (p < .05). This dietary treatment dramatically improved gut microflora by decreasing the population of Escherichia coli and increasing the Lactobacillus spp.:E. coli ratio. Based on our investigations, supplementation of organic acids and probiotics in chick diets can increase the ability to digest crude fibre and villus height and decrease intestinal E. coli without impairing growth performance.     

褪黑素对肉鸡生长性能及免疫功能的影响

采用对比试验,将120只1日龄AA肉鸡分为2组(对照组和试验组),每组3个重复,每个重复20只鸡。对照组不添加褪黑素,试验组添加褪黑素10mg/kg,研究褪黑素对肉鸡生长性能及免疫机能的影响。试验结果表明:试验期间,鸡的平均日增重(ADG)、饲料转化率(FCR)差异显著(P<0.05);平均日采食量(ADFI)差异不显著(P>0.05);胸腺、脾脏、法氏囊指数试验组显著高于对照组(P<0.05)。     

Effects of dietary fiber and threonine on performance,intestinal morphology and immune responses in broiler chickens

The present experiment was conducted to investigate the effects of fiber and threonine (Thr) on growth performance, intestinal morphology and immune responses of broiler chickens. A total of 420 one-day-old mixed sex broiler chicks (Ross 308) were randomly divided into 6 experimental diets and 5 replicates of 14 chicks based on a factorial arrangement (2 × 3) from 1 to 42 d of age. Experimental factors included dietary supplemental fiber type (no supplemental fiber [NSF], 30 g/kg sugar beet pulp [SBP] or 30 g/kg rice hull [RH]) and Thr inclusion level (100% or 110% of Thr requirement recommended by breeder company [Ross 308]). Growth performance of broilers was assayed at different periods of the experiment. Intestinal morphometric features were measured at 21 d of age. Antibody titer against sheep red blood cells (SRBC), Newcastle and influenza disease viruses were measured on d 30 of trial. Dietary inclusion of SBP and RH significantly decreased feed intake and weight gain during the entire rearing period (P < 0.05). Interaction of fiber and Thr had no beneficial effects on the performance of chickens across the entire rearing phase. Dietary supplementation of 110% Thr required level improved jejunal morphometric features (P < 0.05), whereas its inclusion with fibrous materials failed to show the same effects. Dietary supplemental Thr together with SBP significantly increased antibody production against SRBC (P < 0.05). In conclusion, although supplemental 30 g/kg fibrous materials impaired growth performance, inclusion of SBP along with 110% Thr level improved the humoral immunity in broiler chickens.     

微胶囊化益生菌对肉鸡生产性能、抗氧化性能和免疫机能的影响

试验旨在研究微胶囊化益生菌对肉鸡生产性能、抗氧化水平和免疫机能的影响。选取1日龄爱拔益加(AA)肉仔鸡270只,随机分为3组(每组6个重复,每个重复15只)。对照组饲喂基础饲粮,益生菌组在基础饲粮中添加微胶囊(JM113活菌数为1×10^8 CFU/kg基础饲粮),抗生素组在基础饲粮中添加50 mg/kg金霉素,试验期42 d。结果表明:饲粮添加微胶囊化益生菌和抗生素显著提高了肉鸡平均日增重(P<0.05),降低了料肉比(P<0.05)。饲粮添加微胶囊化益生菌显著增加了肉鸡血清总抗氧化能力和总超氧化物歧化酶活性(P<0.05)。饲粮添加微胶囊化益生菌显著增加了肉鸡血清免疫球蛋白IgA、IgG和IgM水平(P<0.05)。由此可见,饲粮添加微胶囊化益生菌能取得与抗生素相同的促生长效果,并能提高肉鸡抗氧化能力和免疫水平。     

谷氨酸锌对肉仔鸡生长性能、血清含锌酶活性及免疫器官指数的影响

本试验旨在研究谷氨酸螯合锌(zinc glutamine,Glu-Zn)对肉仔鸡生长性能、血清含锌酶活性、免疫器官指数的影响。选用240只7日龄商品代AA肉用仔鸡,随机分成6个处理。1组为对照组饲喂含80mgZnSO4·H2O形式的Zn的基础日粮,其余5组分别在基础日粮中添加20、40、60、80mg/kg和100mg/kg谷氨酸螯合锌形式的Zn。饲养期为35d。结果表明:试验各周及全期,随着日粮中谷氨酸螯合锌水平的增加,肉仔鸡日增重和饲料转化效率均得到改善,同时,40mg/kg谷氨酸螯合锌组显著提高了试验全期的平均日增重(P0.05);血清碱性磷酸酶活性随着日粮锌水平的增加先上升,而后又下降,在锌添加水平为60mg/kg时取得最大值;谷氨酸螯合锌组在胸腺指数、脾脏指数上,明显优于对照组,且存在显著差异(P0.05),而法氏囊指数并不敏感。从本试验各项指标和经济效益综合分析,建议肉仔鸡饲料中添加60mg/kg的谷氨酸螯合锌。     

Effects of different dietary sources and levels of selenium supplements on growth performance,antioxidant status and immune parameters in Ross 308 broiler chickens

1. Although different impacts of various sources of selenium (Se) on chicken performance have been largely studied, there is a lack of comparative experiments studying the effects of these sources on the immune system and antioxidant indices of broiler tissues. The aim of this study was to examine the effects of various sources and levels of dietary Se supplements on performance, antioxidant status and immune parameters in Ross 308 broiler chickens.

2. A total of 1200 1-d-old male broilers (Ross × Ross 308) were divided into 8 treatments with 6 replicate pens and 25 birds per pen. This experiment was conducted as a completely randomised design with a 4 × 2 factorial arrangement. Main factors included Se sources as sodium selenite (SS), Se-enriched yeast (SY), DL-selenomethionine (SM) and nano-selenium (NS) and levels at 0.1 or 0.4 mg/kg Se.

3. Dietary supplementation of organic Se sources significantly improved average daily gain (ADG), gain: feed ratio and European production efficiency factor (P < 0.05) compared to birds fed on diets supplemented with inorganic source. In addition, ADG was increased in response to increased level of supplemental Se. Based on contrast comparison, there were significant differences in these parameters between organic versus inorganic sources of Se. However, there was no difference between contrast comparisons of NS versus SM and SY.

4. Total anti-sheep red blood cell (SRBC) and Immunoglobulin G (IgG) titres and hypersensitivity were enhanced by increasing supplemental concentration of Se and using organic sources of Se rather than SS (P < 0.05).

5. Oxidation resistance assessment of tissues demonstrated that supplementation of organic sources of Se and increase in supplemental concentration of Se ameliorated glutathione peroxidase activity, total antioxidant capacity and malondialdehyde formation (P < 0.05). Mostly, there were significant differences between organic versus inorganic sources of Se in oxidation resistance.

6. Overall, dietary supplementation of 0.4 mg/kg Se from an organic source resulted in better production performance and immune system response. Moreover, minimum formation of malondialdehyde in broiler tissue was observed in birds fed on diets supplemented with SM at 0.4 mg/kg.

7. It can be concluded that SM is more effective than other sources of Se in reducing lipid oxidation.     

Production performance,immune response and blood biochemical parameters in broiler chickens fed diet incorporated with prebiotics

This experiment was conducted to identify the suitable replacer of broiler feed antibiotics with prebiotics (mannan oligosaccharides‐MOS or fructooligosaccharide‐FOS). Two hundred and forty (240)‐day‐old chicks were randomly divided into 30 groups (6 treatments x 5 replicates/treatment x 8 chicks/replicate). Six experimental diets T₁, T₂, T₃, T₄, T₅ and T₆ were formulated to contain an additional 0, antibiotic, that is, bacitracin methylene di‐salicylate (BMD) @20 mg/kg, MOS (0.1% and 0.2%) and FOS (0.1% and 0.2%) respectively. Body weight gain was significantly (p < 0.05) increased in MOS‐0.2% supplemented group at 0–21 d and 0–42 d of broiler chicken. Humoral and in vivo cell‐mediated immune response were significantly improved (p < 0.05) in BMD, MOS @0.1% or 0.2% treated group. Significant (p < 0.05) increase was recorded in total protein (except 21 d), albumin and aspartate amino transferase (AST) and decrease (p < 0.05) in alanine amino transferase (except 42 d), cholesterol and uric acid concentration. The weight of breast, thigh, back, drumstick bursa of Fabricius and thymus were higher (p < 0.05) in the birds given the MOS @0.2% (T₄). It is concluded that MOS @0.2% may be suitable replacer of antibiotic growth promoter, and it has a beneficial effect on production performance, immune responses, blood biochemical parameters and cut up parts in broiler chickens.     

Effect of essential oils or saponins alone or in combination on productive performance,intestinal morphology and digestive enzymes' activity of broiler chickens

This study was carried out to evaluate the effect of essential oils or saponins alone or in combination on productive performance, intestinal morphology, and digestive enzymes' activity in broilers. Four hundred one-day-old male broiler chickens were randomly assigned to four treatments, each with 5 replicates. The birds were fed experimental diets contained either no phytogenic feed additives (control) or were supplemented with 25.0 mg/kg of an essential oil blend from star anise, rosemary, thyme and oregano (essential oils); 46.0 mg/kg of a Quillaja saponin blend (saponins); or a combination of both phytogenic preparations (essential oils plus saponins). The experiment lasted for 42 days. Body weight, feed intake and weight gain were recorded weekly, and the feed conversion ratio was calculated, throughout the experiment. Intestinal morphology and digestive enzymes' activity were determined at the end of the experiment. It was found that the body weight was increased by all dietary supplements at the end of the experiment. There was no change in performance parameters among the treatments during the starter period. At the grower period and the overall experiment, the weight gain of birds was higher in all supplemented groups compared to the control, but the feed conversion was better in the essential oils with saponins treatment. Supplementation of essential oils or saponins alone or in combination increased the villus height and the villus/crypt ratio of the intestine. There was an increase in trypsin, chymotrypsin and elastase activities in the essential oils plus saponins group only. The obtained results indicate that the phytogenic feed additives, especially essential oils with saponins, can be considered as new promising agents in promoting the growth performance of broilers. The effect could be related to its improving impact in intestinal development and increasing the protease enzymes' activity, resulting in increased protein digestibility and absorption of dietary nutrients.     

Effects of salinomycin and Bacillus subtilis on growth performance and immune responses in broiler chickens

The present study was undertaken to compare the effect of salinomycin and Bacillus subtilis on growth performance, serum antibody levels against Clostridium spp. and Eimeria spp., and cytokine mRNA expression levels in broiler chickens raised in the used litter. Broiler chickens fed a diet containing salinomycin showed lower (P < 0.05) body weights compared with the control diet-fed counterparts. Serum nitric oxide levels were significantly (P < 0.05) elevated in chickens fed the B. subtilis-enriched diet compared with those on either the salinomycin-fed or control diet-fed chickens. None of the dietary treatments affected (P > 0.05) serum antibody levels against Clostridium perfringens toxins. Both salinomycin and B. subtilis significantly lowered (P < 0.05) the serum levels of Eimeria-specific antibodies compared with the control group. Salinomycin, but not B. subtilis, significantly modulated (P < 0.05) the expression of cytokines encoding interferon-γ (IFN-γ), interleukin10 (IL-10) and tumor necrosis factor superfamily 15 (TNFSF15) compared with the control group. In conclusion, dietary salinomycin and B. subtilis affected serum anticoccidial antibody and intestinal cytokine expression, but failed to improve growth performance in broiler chickens. Further study is warranted to investigate the mode of action of salinomycin on host immune response and growth performance in broiler chickens.     

Conditioning time and sodium bentonite affect pellet quality,growth performance,nutrient retention and intestinal morphology of growing broiler chickens

ABSTRACT

1. The present study was conducted to evaluate the effects of conditioning times and processed sodium bentonite (PSB)-based pellet binder (G. Bind?) on pellet quality, performance, small intestine morphology, and nutrient retention in growing broiler chickens (d 11–24).

2. A total of 540, one-day-old male broiler chicks were fed a commercial starter diet (d 1–10). On day 11, birds were assigned to a 2 × 3 factorial arrangement including two conditioning times (2 and 4 min) and three levels of PSB (0, 7.5 and 15 g/kg) with six replicates of 15 chicks each. Feed intake and weight gain were recorded to calculate growth performance. The jejunal segment and excreta samples were collected to determine intestinal morphology and nutrient retention, respectively.

3. Diets produced with 2 min conditioning time and containing 15 g/kg PSB increased (P < 0.05) pellet durability index and hardness. Conditioning time and PSB levels had no significant effect on growth performance. The inclusion of PSB to broilers diet increased (P < 0.05) energy usage of the pelleting machine. Chickens fed the diet conditioned for 2 min and containing 15 g/kg PSB had the lowest (P < 0.05) relative jejunal length. Two minutes conditioning of diets containing 15 g/kg PSB increased (P < 0.05) apparent metabolisable energy retention in broilers.

4. It was concluded that 2 min conditioning of diet containing 15 g/kg PSB improved pellet quality and nutrient retention of broiler chickens, while the main effects of conditioning time and PSB levels were controversial in most evaluated parameters.