Growth Promoters In Broiler Diets Research Articles

Effects of the Fibrous Root of Polygonatum cyrtonema Hua on Growth Performance, Meat Quality, Immunity, Antioxidant Capacity, and Intestinal Morphology of White-Feathered Broilers.

This study was designed to evaluate the effects of different doses of the fibrous roots of Polygonatum cyrtonema Hua on the growth performance, slaughter parameters, meat quality, immune function, cytokines, antioxidant capacity, and intestinal morphology of white-feathered broilers. Also, the mechanism to improve immune functions of broilers was explored through network pharmacology and molecular docking technology. A total of 360 AA-white-feathered broilers were randomly divided into six groups (not separated by sex), with six repetitions per group (n = 10). The groups were as follows: basal diet (CON group), basal diet supplemented with 300 mg/kg aureomycin (ANT group), basal diet supplemented with 2%, 3%, and 4% fibrous root raw powder (LD, MD, and HD group), or basal diet supplemented with 3% fibrous root processed powder (PR group), in a 42-day experiment. The dietary inclusion of P. cyrtonema fibrous roots increased slaughter performance (p < 0.05), reduced the fat rate (p < 0.05), improved intestinal morphology (p < 0.05), and improved the immune organ index to varying degrees. It also significantly improved pH reduction, drip loss, and pressure loss of breast muscle and leg muscle (p < 0.05). Furthermore, it significantly improved immune and antioxidant functions including decreased MDA content of serum (p < 0.01), increased GSH-Px content (p < 0.01), IgG, IgA, and C4 contents (p < 0.05), and increased expression of IL-2 and IFN-γ (p < 0.01). Additionally, the mechanism by which fibrous roots improve immune function in broilers was explored using network pharmacology and molecular docking technology. Network pharmacology and molecular docking revealed that flavonoids such as baicalein, 4',5-Dihydroxyflavone, 5,7-dihydroxy-6,8-dimethyl-3-(4'-hydroxybenzyl)-chroman-4-one, and 5,7-dihydroxy-3-(2'-hydroxy-4'-methoxybenzyl)-6,8-dimethyl-chroman-4-one were key components that enhanced immune function through the MAPK1 and other key targets involved in regulating the MAPK signaling pathway. From the findings, it can be concluded that incorporating P. cyrtonema Hua fibrous root as a natural feed supplement and growth promoter in broiler diets had a positive impact on bird health and performance.

Feeding Nigella sativa oil to broilers affects their performance, serum constituents and cecum microbiota

The objective of this study was to assess the effect of supplementation of Nigella sativa oil (NSO) as a growth promoter in broiler diets. A total of 300 unsexed one-day-old Arbor Acre broiler chicks were randomly divided into five treatment groups (60 chicks/group). Each group was divided into five replicates with 12 chicks per replicate. Group 1 was fed on the basal diet with no additives (control). Group 2 was fed the basal diet supplemented with oxytetracycline (OTC) at the level of 50 ppm. Groups 3, 4 and 5 were fed the basal diet supplemented with 500, 1000 and 1500 ppm NSO, respectively. Birds fed on 1500 ppm NSO diet showed the heaviest body weight at 14, 28 and 42 days of age. Feed conversion ratio was significantly improved at all ages with the inclusions of OTC and NSO generally superior to the control group. The relative weight of spleen was increased significantly by the addition of NSO at various levels. However, relative weights of thymus and bursa were not altered by the treatments. Total bacterial count, total yeast and moulds count, E. coli and salmonella spp. counts were reduced significantly, whereas the total lactic acid bacteria count was increased in OTC and NSO groups compared with control. Nigella sativa oil could be used in broiler chicken feeds as a natural alternative to antibiotic growth promoters to improve gut health and consequently growth performance.

Efficacy of using zinc oxide nanoparticle as a substitute to antibiotic growth promoter and zinc sulphate for growth performance, antioxidant capacity, immunity and intestinal barrier function in broilers

Dietary zinc oxide nanoparticle (ZnO NP) possessing multiple biological activities might be a potential substitute for the combination of ZnSO4 and antibiotic growth promoter in broiler diets. Therefore, this study was conducted to investigate the efficacy of dietary ZnO NP as a substitute to the combination of ZnSO4 and xanthomycin for growth, antioxidant capacity, immunity, intestinal barrier and liver function in broilers. Arbor Acres chicks (n = 320) were assigned to 5 treatments with 8 replicates. Birds received a basal diet supplemented with 80 mg/kg ZnSO4 plus 5 mg/kg xanthomycin (ZnSO4 + Xanthomycin) or 0 (negative control, NC), 40, 80, and 160 mg/kg ZnO NP for 42 days. The average daily gain, average daily feed intake and feed-to-gain ratio showed dose-dependent increases with the increasing level of dietary ZnO NP during the 21–42 day and 1–42 day stages. The final body weight (42 d) and serum concentrations of insulin-like growth factor 1 and growth hormone increased linearly with the increasing level of dietary ZnO NP. In addition, 80 mg/kg ZnO NP increased the serum concentrations of IgA, IgG, IgM, andinterleukin-10 and peroxidase activity, the jejunal mucosal villus height, villus width and goblet cell numbers. Dietary 80 or 160 mg/kg ZnO NP significantly altered mRNA abundances of genes related to antioxidant status, intestinal barrier and immunity in the jejunal mucosa. These results indicated that dietary supplementation with 40–160 mg/kg ZnO NP caused no obvious negative effects on liver function, but effectively improved growth performance, intestinal barrier function, immunity and antioxidant capacity. Highlights Dietary 40–160 mg/kg zinc oxide nanoparticle (ZnO NP) improved growth performance and enhanced immunity of broilers without obvious negative effects on liver function. Dietary 40–160 mg/kg ZnO NP improved intestinal barrier and intestinal morphology, and enhanced antioxidant capacity via Nrf2/HO-1 pathway. Doses of 40–80 mg/kg ZnO NP were suggested to alternate the combination of 80 mg/kg ZnSO4 and 5 mg/kg xanthomycin in diets of broilers.

Bacteriophage cocktail supplementation improves growth performance, gut microbiome and production traits in broiler chickens

BackgroundEffective antibiotic alternatives are urgently needed in the poultry industry to control disease outbreaks. Phage therapy mainly utilizes lytic phages to kill their respective bacterial hosts and can be an attractive solution to combating the emergence of antibiotic resistance in livestock.MethodsFive hundred and four, one-day-old broilers (Ross 308) were allotted to 1 of 4 treatment groups in a completely randomized design. Treatments consisted of CON (basal diet), PC (CON + 0.025% Avilamax®), BP 0.05 (CON + 0.05% bacteriophage), and BP 0.10 (CON + 0.10% bacteriophage).ResultsA significant linear effect on body weight gain (BWG) was observed during days 1–7, days 22–35, and cumulatively in bacteriophage (BP) supplemented groups. The BWG tended to be higher (P = 0.08) and the feed intake (FI) was increased (P = 0.017) in the PC group over CON group. A greater (P = 0.016) BWG and trends in increased FI (P = 0.06) were observed in the experiment in birds fed PC than CON diet. At the genus level, the relative abundance of Lactobacillus was decreased in PC (65.28%), while it was similar in BP 0.05 and BP 0.10 (90.65%, 86.72%) compared to CON (90.19%). At the species level, the relative abundance of Lactobacillus salivarus was higher in BP 0.05 (40.15%) and BP 0.10 (38.58%) compared to the CON (20.04%) and PC (18.05%). A linear reduction in the weight of bursa of Fabricius (P = 0.022) and spleen (P = 0.052) was observed in birds fed graded level of BP and an increase (P = 0.059) in the weight of gizzard was observed in birds fed PC over BP diets. Linear and quadratic responses were observed in redness of breast muscle color in birds fed graded level of BP.ConclusionsThe inclusion of the 0.05% and 0.1% BP cocktail linearly improved broiler weight during the first 7 days, 22–35 days and cumulatively, whereas 0.05% BP addition was sufficient for supporting immune organs, bursa and spleen as well as enhancing gut microbiome, indicating the efficacy of 0.05% BP as a substitute antibiotic growth promoter in broiler diets.

Effects of nanoencapsulated cumin essential oil as an alternative to the antibiotic growth promoter in broiler diets

Summary The effects of nanoencapsulated cumin essential oil (EO) feeding broilers on growth performance, mucin 2 gene expression, blood parameters, and immune responses to phytohemagglutinin (PHA) and 2, 4-dinitrochlorobenzene (DNCB) were evaluated. In a completely randomized design, 1050 male day-old Ross 308 broilers were distributed into 7 dietary treatments with 5 replicates of 30 birds per replication. Dietary treatments included 1) control basal (no additives), 2) control antibiotic growth promoter (flavophospholipol at 650 mg/kg), control basal plus a solution of 3) 150 mg/kg of chitosan nanoparticles, free-form cumin EO at 4) 100 or 5) 200 mg/kg, and nanoencapsulated cumin EO at 6) 100 and 7) 200 mg/kg. The use of 200 mg/kg nanoencapsulated cumin EO significantly (P

Comparison of performance and feed digestibility of the non-antibiotic feed supplement (Novacid) and an antibiotic growth promoter in broiler chickens.

Antibiotic growth promoters have been widely used in poultry to improve overall performance. The emergence of antibiotic resistance has resulted in sanctions imposed on the use of antibiotics in poultry diets, and alternatives such as herbal extracts are being considered to improve growth performance. The aim of this study was to compare the performance and feed digestibility of the feed supplement Novacid, which contains organic acids, glucomannan, and phytochemicals, with that of the antibiotic growth promoter bacitracin methylene disalicylate (BMD) in commercial broiler chickens. Six hundred 1-d-old Ross × Ross 308 male broiler chicks were randomly and equally assigned to six treatment groups with five replicates each (20 chicks per replicate). The chicks were fed a corn-soybean meal basal diet, and divided into two groups: unchallenged and challenged with E. coli (400mg/kg Escherichia coli inoculation). Each of these groups was divided into three study groups: untreated, treated with 0.05% Novacid, and treated with 400mg/kg BMD. At day 42, inclusion of Novacid or BMD significantly (P < 0.05) improved the performance in the unchallenged groups relative to the control group. However, in E. coli-challenged groups, Novacid and BMD did not improve performance. Ileal digestibility of crude fat, crude protein, and gross energy were reduced in the Novacid group (P < 0.05). BMD and Novacid were equally effective in controlling ileal nutrient digestibility and feed coliform count (P < 0.05). Novacid reduced cecal E. coli and Salmonella count compared to BMD and control. Thus, a phytochemical feed supplement with organic acids and glucomannan could be an effective substitute for antibiotic growth promoters in broiler diets, but cannot replace antibiotics to counter potent infectious agents such as E. coli.

Feeding broilers with thyme essential oil loaded in chitosan nanoparticles: an efficient strategy for successful delivery

ABSTRACT1. The use of chitosan nanoparticles (CNPs) for the entrapment of active components has gained considerable interest in food and pharmaceutical industries due to its mucous adhesiveness, non-toxicity, biocompatibility and biodegradability.2. This study aimed to investigate the usefulness of feeding encapsulated thyme essential oil (E-TEO) on performance, blood parameters, immunity and ileal microflora in broilers.3. CNPs were prepared by using ionotropic gelation and structurally characterised by dynamic light scattering; scanning electron microscope and Fourier transform infrared spectroscopy. The encapsulation efficiency percentage of TEO in CNPs and its in vitro release were determined using ultraviolet visible spectroscopy and dialysis method, respectively.4. An in vivo experiment was conducted with five treatments of five replicates with ten chicks per pen. Dietary treatments consisted of an unsupplemented control diet, or supplemented with chlortetracycline (80 and 50 mg/kg during the starter and grower phase, respectively); CNPs (60 mg/kg); TEO (40 mg/kg diet) or E-TEO (60 mg/kg).5. Results showed uniform distribution of nanoparticles with roughly spherical morphology, and the size of particles ranged from 30 to 100 nm. It was observed that 68.3% of TEO was encapsulated into CNPs, from which more than 90% was released within the first 96 h. Birds treated with antibiotic and E-TEO showed significantly (P < 0.05) higher body weight gain than the control and the other treatments were intermediate. Compared to the control group, adding of E-TEO into diet significantly (P < 0.05) improved feed conversion ratio at 42 days of age. Feeding birds with E-TEO significantly (P < 0.05) decreased the number of coliform and total aerobic bacteria compared to other treatments. Birds supplemented with E-TEO showed lower heterophile to lymphocyte ratio compared to birds that received TEO.6. The results suggested that the entrapment of TEO in CNPs and its sustained release promoted broiler performance via the improvement of physiological status and modulating intestinal microbiota and therefore could be used as substitute for antibiotic growth promoter in broiler diets.

Effect of laboratory-isolated Lactobacillus plantarum LGFCP4 from gastrointestinal tract of guinea fowl on growth performance, carcass traits, intestinal histomorphometry and gastrointestinal microflora population in broiler chicken.

The study aimed to investigate the effect of feed supplements, viz Lactobacillus plantarum LGFCP4 (laboratory isolate from GIT of Guinea fowl), Lactobacillus acidophilus (NCDC, Karnal) and in-feed antibiotic bacitracin methylene disalicylate (BMD) on growth performance, FCR, carcass traits and immune organs weight, intestinal histomorphometry and gastrointestinal microflora population in broiler chickens. In a completely randomized design, CARIBRO-Dhanraja broiler chicks (n=160) were used with four treatment groups. During the entire experimental duration of 35days, treatment groups were provided with different dietary treatments (T1 - basal diet (negative control), T2 - antibiotic growth promoter BMD 20g/100kg feed (positive control), T3 - 1×108 cfu of L.acidophilus/gm-fermented feed +MOS 1g/kg feed and T4 - 1×108 cfu of laboratory-isolated L.plantarum LGFCP4/gm-fermented feed+ MOS 1g/kg feed. After 35days of experimental period, no significant results have been observed in different growth performance traits among treatment groups. Cut-up parts and edible organs' weight remained unaffected by dietary supplementation, whereas weight of immune organs were significantly higher (p<0.05) in L.plantarum LGFCP4-supplemented group. At the end of feeding trial, significantly (p<0.05) lower E.coli count was observed in crop of T4 birds, while in ileum, T2 and T3 showed lower count. In caeca, T2 group showed lowest E.coli count. Salmonella count in crop and ileum was significantly (p<0.05) low in T3 and T4, while in caeca, T2 group showed lowest count. In terms of histomorphometry, duodenal villous height (VH), crypt depth (CD) and VH:CD ratio were higher for T3 and T4 and lowest values were obtained for T2 group. The results of the study showed that L.plantarum LGFCP4 isolated from GIT of guinea fowl can effectively replace in-feed antibiotic growth promoters in broiler diets by altering intestinal villi morphology and improving the gut health by reducing the pathogenic microbial load.

A blend of benzoic acid and essential oil compounds as an alternative to antibiotic growth promoters in broiler diets

The discussions about the possibility of bacterial resistance resulting from the use of antimicrobial growth promoters in broiler feed. The limitations of international market have forced the exporting countries to search for alternatives to ensure the animal growth without affecting the quality of the final product. An experiment was conducted to evaluate the efficacy of in-feed CRINA® Poultry Plus (CPP, a mixture of benzoic acid and essential oils) in enhancing broiler growth performance and reducing coccidial lesions, as a non-antibiotic growth promoter. Effect of CPP on litter moisture content was also assessed. The treatments were: NC, a basal diet without growth promoters; PC, a basal diet with 10 ppm of Avilamycin (AVI); CPPD, a basal diet with 300 ppm of CPP from 1 to 42 d; AVI(1–21d)/CPP(22–42d), a basal diet with 10 ppm of AVI from 1 to 21 d and 300 ppm of CPP from 22 to 42 d; and AVI + CPP (1–42 d), a basal diet with 10 ppm of AVI and 300 ppm of CPP from 1 to 42 d. The 5 treatments were applied in a completely randomized arrangement and 10 replicate with 31 birds per pen. The diets with CPP increased body weight gain and feed conversion rates in the 1 to 42 d period and European productive efficiency index compared to birds fed with negative control diet (NC). Furthermore, lesion scores induced by E. acervulina were highest in the NC. The results suggest that CRINA® Poultry Plus can be used as an alternative to antibiotic growth promoters in broiler diets without losses in productive performance.

Influence of Dietary Supplementation of Synbiotics as an Alternative to Antibiotic Growth Promoters on Performance, Ultrastructure and Histomorphology of Gut Integrity in Broilers

Although beneficial effects of the most growth promoters are revealed particularly when flocks encounter stress conditions, in the present study regarding effects of the growth promoters on growth performance and intestinal histomorphometry, it might be concluded that synbiotic @ 250mg/kg in diet could be considered as a suitable alternative for antibiotics as a growth promoter in broiler diets.

Effect of Spearmint (Mentha spicata) on Performance and Blood Serum Parameter of Broiler

The present study was planned to evaluate the response of broiler chicks to diets containing graded levels of spearmint (Mentha spicata). A total of 200 , five days-old, unsexes (cob) broiler chicks were used. Chicks were weighed individually and assigned randomly to five groups of 40 chicks per treatment and each treatment was subdivided to four replicates of 10 chicks each. Five experimental diets were formulated (A, B, C, D and E) to meet the nutrient requirements of broiler chicks. The experimental parameters examined were growth performance, serum metabolite, electrolyte and enzyme activities and economic appreciable. Diet (A) Negative Control (NC), a basal diet without antibiotic or spearmint, diet B as Positive Control (PC) basal diet supplemented with antibiotic (Neomycin 16 mg/Kg), diets C,D and E were basal diet supplemented with spearmint at levels of 1,1.5,and 2%, respectively. Result obtained showed that addition of spearmint improved significantly (P&lt;0.05) the performance (body weight gain and feed conversion ratio) of broiler chicks compared to group fed on NC while no significant (P&lt;0.05) differences between chicks fed on diets supplemented with spearmint and PC group observed, no significantly difference was found in feed consumption between all treated groups. The mortality rate did not influenced by the dietary treatments. Results revealed no significant differences (P&lt;0.05) observed among all treatment groups in the carcass dressing percentages, Supplementation of broiler diets with spearmint at various levels was resulted in significant (p&gt;0.05) reduction of abdominal fat, serum cholesterol, and AST enzyme activity compared to both NC and PC groups while the levels of urea, total protein, glucose and ALP and serum electrolytes levels remained unchanged. The highest profitability ratio (1.13) was obtained from the diet (E) supplemented with 2% spearmint. This study showed that spearmint when added as growth promoter in broiler diets has a similar effect on performance as that of antibiotic without any adverse effects.

β-mannanase and mannan oligosaccharides in broiler chicken feed

The study aimed to evaluate the use of β-mannanase and mannan oligosaccharides (MOS) to replace growth promoters in broiler diets. Four hundred male Cobb broiler chicks were used, with initial weight of 45±1g, distributed in a completely randomized design with five treatments and eight repetitions of ten birds. The treatments were: basal feed; basal feed without growth promoter; basal feed without growth promoter + β-mannanase; basal feed without growth promoter + MOS; and basal feed without growth promoter + β-mannanase + MOS. The feed intake of the birds increased in response to dietary treatments compared to basal diet during the period 1-21 days of age. A higher weight gain and improved feed conversion was found at 42 days of age among birds that had received the basal diet without growth promoter + MOS. The absolute weight at slaughter, relative carcass and prime cuts except breast weights improved in response to dietary treatments compared to the basal diet at 42 days of age. No difference was observed in relative weight of the liver, while significant differences were found in the weight of heart, gizzard, and abdominal fat. It was concluded that β-mannanase and MOS can replace the growth promoters in broiler diets without compromising production and economic performance. However, the association of these products into the feed may cause negative interaction that reduces the broiler chickens' performance

Growth Performance and Histological Changes in Ileum and Immune Related Organs of Broilers Fed Organic Acids or Antibiotic Growth Promoter

An experiment was designed to evaluate the effects of using organic acids as an alternative to antibiotic growth promoter on performance of broiler chicks. Carcass characteristics, histological changes of ileum and immune related organs (bursa, thymus and spleen) along with intestinal bacteria count were also studied. A number of 150 Cobb broiler chicks were fed on three dietary treatments: a basal cornsoybean meal diet served as a control treatment with no supplements or supplemented with either 0.025% Bacitracin Methylene Disalicylat (BMD, antibiotic) or 0.06% Galliacid (organic acids) from 10 to 36 days of ® age. The results showed that birds fed antibiotic or organic acids gained significant (p<0.05) more body weight than those fed the control diet. No significant differences were detected among treatments on feed intake while feed conversion ratio (FCR) values were significantly (p<0.001) differ. Addition of organic acids or antibiotic did improve FCR by about 9 and 4%, respectively. These results indicated that birds fed either organic acids or antibiotic supplemented diets utilized feed more efficiently than those fed the control diet. Carcass characteristics were not affected by dietary treatments, while the addition of antibiotic or organic acids significantly (p<0.01) increased spleen and bursa weight (% live body weight). Addition of organic acids was more effective than antibiotic on decreasing intestinal count of Escherichia coli and appearance of Colostridium perfringers. Organic acids as alternative to the antibiotic growth promoter have stimulated some histological change in histology of the villi and the immune related organs. Performance and feed efficiency are closely interrelated with the quantitative microbial load of the gut, the morphological structure of the intestinal wall and the activity of the immune system. In conclusion, dietary inclusion of organic acids increased growth performance and improved intestinal health and morphology of broiler chicks. It could be successfully used as alternative to antibiotic growth promoters in broiler diets or as a tool of controlling intestinal pathogenic bacteria.

Satureja hortensis as a growth promoter in broiler chickens

Summary Satureja hortensis is a popular herb in most regions of the world with leaves used as seasoning. Evidence shows that this plant contains phenolic components such as thymol and carvacrol with a relatively wide spectrum of antimicrobial activity. This study aimed at evaluating the efficacy of S. hortensis plant powder as an alternative to antimicrobial growth promoters in broiler diets. The plant was bought in sufficient quantity from the district of Yasouj, Iran and was dried and ground into powder. A total of 140 unsexed 1-day-old Arbor Acers breed broiler chicks were housed and fed a starter diet up to 18 days of age. The birds were then randomly divided into two groups and reared under similar conditions. Chickens received either normal grower (from 18 to 35 days of age) and finisher (from 36 to 50 days of age) diets without S. hortensis (group I) or a similar diet containing one percent plant powder (group II). Statistical comparison of average body weights at various time intervals showed that chickens in group II (1930 ± 29 g, n=63) were significantly (P<0.05) heavier than the birds in the control group (1837 ± 25 g, n=62). The average body weight of males in each group (2075 ± 42 g, n=20 and 2143 ± 40 g, n=22 for groups I and II, respectively) was also greater than those of the females (1724 ± 34 g, n=42 and 1808 ± 30 g, n=41 for groups I and II, respectively). Although feed conversion ratio was slightly less in group II (1.95), it was not substantially different from that in group I (2.02). It is concluded that S. hortensis might be a potential growth promoter in poultry.

NUTRITIVE VALUE OF SKIMMED MILK AND WHEY, ADDED AS NATURAL PROBIOTICS IN BROILER DIETS

Present study investigated the effect of adding either commercial or natural probiotics to broilers diets on growth performance, nutrients digestibility and economical efficiency. Avi-Bac (a probiotic product of concentrated lactic acid bacteria and enzymes) was used as a commercial probiotic, while fresh skimmed milk and whey were used as a natural probiotics. Nine hundred one-day-old unsexed Hubbard broiler chicks were randomly distributed into 6 experimental groups, of 150 broilers, with 3 replicates for each treatment group. All diets were formulated to contain the tested levels of both commercial and natural probiotics and were fed in a mash form. The experimental diets were fed in 2 phases: grower (1-4 wk) and finisher (5-6 wk). Avi-Bac was used at level of 0.1%, while skimmed milk or whey were added at levels of 0.5 or 1.0% of the diet. Water and feed were offered ad-libitum throughout the experimental period, which lasted 6-weeks. Broilers receiving the diets supplemented with commercial and natural probiotics showed significantly (P 0.05) in crude fiber digestibility. Also, the data showed that adding both natural or commercial probiotics to broiler diets improved the average values of calculated economical efficiency. The obtained results indicated that natural or commercial probiotic can be used as a growth promoter in broiler diets and it can improve performance, nutrient digestibility and economic efficiency of broilers.

Influence of different levels of humic acid and esterified glucomannan on growth performance and intestinal morphology of broiler chickens

A study was under taken to investigate the effect of dietary supplementations of humic acid and esterified glucomannan) on broiler performance and the morphological measurements of small intestine. Two hundred and ten day old broiler chicks were weighed and randomly assigned to seven treatment groups in triplicate. The dietary treatments included T1) control (basal diet without any additives), T2) basal diets supplemented with 0.1% humic acid, T3) basal diets supplemented with 0.2% humic acid, T4) basal diets supplemented with 0.3% humic acid, T5) basal diets supplemented with 0.1% esterified glucomannan, T6) basal diets supplemented with 0.2% esterified glucomannan and T7) basal diets supplemented with 0.3% esterified glucomannan. Different parameters including body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR) and morphology of small intestine were evaluated during six weeks of experimental period. According to the results, at the end of experimental period, the highest average BWG were recorded in T4 group (fed with 0.3% humic acid), compared to control (T1) and other experimental groups (p < 0.05). Where as, the highest body weight gain were observed during starter period in treatment 7 (fed with 0.3% esterified glucomannan) as compare to other experimental groups (p < 0.05). Statistically, feed intake remained unaffected during the experimental period in all the treatment groups. However, the lowest and the highest feed intake were observed numerically within treatments T4 and T1 with 4229.70 g and 4362.30 g, respectively. Addition of dietary supplements used in the study appeared to have significant effect on the morphology of the small intestine (jejunum mucosal development) of the broilers in different treatment groups. Compared to control group, the inclusion of either humic acid or esterified glucomannon decreased (p < 0.01) the crypt depth and increased villus height respectively (p < 0.05). More ever, the diet supplements with humic acid 0.3% (T4) decreased crypt depth compared to esterified glucomannan and control. The dietary supplementations resulted in an increase in the villus height of intestinal mucosa of broilers. The increase in the villus height was associated with improvement of growth performance for both humic acid and esterified glucomannan. Based on our results it appeared that humic acid and esterified glucomannan can be used as a growth promoter in broiler diets and they can improve the gut health too.

Mananoligossacarídeos em dietas para frangos de corte

Objetivou-se avaliar dietas contendo mananoligossacarídeos (MOS) como aditivo alternativo aos promotores de crescimento por meio do estudo da morfometria do intestino e do desempenho de frangos de corte. Para tanto, 1280 pintos de corte foram distribuídos em delineamento inteiramente casualizado com quatro tratamentos (controle negativo, CN: dieta isenta de antibiótico; controle positivo, CP: dieta contendo antibiótico e duas dietas, MOS 1 e MOS 2, nas quais foram adicionadas ao CN duas fontes distintas de MOS) e oito repetições, sendo a unidade experimental composta por 40 aves. Para submeter as aves ao desafio sanitário, foi formulada uma dieta basal com milho, farelo de soja e farinha de carne e ossos. Adotou-se cama reutilizada, limpeza dos bebedouros duas vezes por semana e oferta semanal de água contaminada com cama. Foram avaliadas altura de vilo e profundidade de cripta do duodeno, jejuno e íleo, consumo da dieta, peso médio, ganho de peso e conversão alimentar das aves. Houve melhora na profundidade de cripta no jejuno e na altura de vilo no íleo das aves alimentadas com dietas contendo MOS. A adição de MOS, independente da fonte, resultou em melhor conversão alimentar em relação às aves do CN, sendo similares às aves do CP. Os mananoligossacarídeos podem ser utilizados como aditivo alternativo aos promotores de crescimento em dietas para frangos de corte, porém, dependendo da fonte, esta pode acarretar em pequenas diferenças no desempenho das aves.

Effect of supplementation of Bacillus subtilis LS 1-2 to broiler diets on growth performance, nutrient retention, caecal microbiology and small intestinal morphology

Present study investigated the effect of dietary supplementation of Bacillus subtilis LS 1-2 on growth performance, apparent nutrient retention, caecal microbial population and intestinal morphology in broilers. Three hundred and twenty day-old Ross broiler chicks were randomly allotted to four treatments on the basis of BW in a randomized complete block design. Experimental diets were fed in two phases: starter (d0–21) and finisher (d22–35). Dietary treatments were basal diet supplemented with 0% (control), 0.15%, 0.30% and 0.45% B. subtilis LS 1-2. Supplementation of increasing levels of B. subtilis LS 1-2 showed linear improvement (P<0.05) in growth performance and apparent nutrient retention. At d35, birds supplemented with increasing levels of B. subtilis LS 1-2 showed decrease in caecal Clostridium and Coliform count (linear, P<0.05). Moreover, supplementation of B. subtilis LS 1-2 increased (linear, P<0.05) villus height and villus height to crypt depth ratio in both duodenum and ileum. Results obtained in the present study indicate that B. subtilis LS 1-2 can be used as a growth promoter in broiler diets and can improve intestinal microbial balance and gut health of broilers.

Assessment of yeast cell wall as replacements for antibiotic growth promoters in broiler diets: effects on performance, intestinal histo‐morphology and humoral immune responses

The study compared the effects of an antibiotic growth promoter (AGP), yeast (Saccharomyces cerevisiae) and yeast cell wall (YCW) on performance, microbiology and histo-morphology of the small intestine and humoral immune responses in Ross 308 broilers. The treatments (eight replicates/treatment, n = 12/replicate) were negative control (NC, without AGP), positive control (PC, supplemented with bacitracin methylene disalicylate, 400 mg/kg), Y and YCW (supplemented with yeast and YCW, respectively, 1000 mg/kg). Live weight at 42 days improved (p = 0.086) in the PC, Y and YCW groups. Feed conversion ratio was better (p = 0.039) in the YCW group compared with the other groups. Antibiotic growth promoter in the PC group shortened the villi in duodenum (p = 0.044). Mucosal Escherichia coli number was higher in the PC group (p < 0.001), whereas in the digesta E. coli number was lower (p = 0.001) in the PC, Y and YCW groups in relation to the NC. Mucosal Salmonella populations increased (p = 0.0001) in the PC group, whereas in the digesta, all treatments reduced the Salmonella (p = 0.0001). Following oral challenge with Salmonella pullorum, YCW increased E. coli numbers on the mucosa (p < 0.001) whereas in the digesta the Y group had lower (p < 0.0001) number of E. coli. In the digesta, Salmonella count was lower in the YCW group compared with the other treatments (p < 0.01). Yeast cell wall -treated birds exhibited better (p < 0.05) humoral immune response against Newcastle disease which was far more persistent over time than in any other treatments. It was concluded that the yeast and the yeast cell wall may have effects identical to BMD on performance of broilers and thus may constitute an effective replacement strategy in the dietary regimens for broiler chickens.

Effect of Using Organic Acids to Substitute Antibiotic Growth Promoters on Performance and Intestinal Microflora of Broilers

A grower broiler experiment (from 14 to 35 days of age) was conducted to study the effect of using two commercial mixtures of organic acids (Galliacid ® and Biacid ® ) to substitute antibiotic growth promoter (Eneramycin ® ) on performance, carcass characteristics and intestinal microflora. 400 (Ross 308) broiler chicks were used. A basal corn-soybean meal diet were formulated and served as a control treatment. The control diet was supplemented with either 0.06% Galliacid, 0.1% Biacid or 0.02% Eneramycin. Birds fed the Galliacid-supplemented diet had 16% (p<0.001) more gain than the control, while those fed the Biacid- or Enramycin- supplemented diets recorded 3 and 5.5% more gain, respectively. Organic acids mixtures and Enramycin supplementation significantly (p<0.001) improved feed conversion ratio. These results indicated that birds fed either organic acid mixtures or Enramycin- supplemented diets utilized feed more efficiently than those fed the control diet. Galliacid significantly (p<0.01) increased dressing percentage and bursa weight (% body weight). No significant differences were detected on liver, spleen and thymus (% body weight) among treatments. Galliacid or Biacid significantly (p<0.001) decreased intestinal Escherichia coli and Salmonella compared to the control and Enramycin-supplemented diets. Dietary Enramycin significantly (p<0.001) decreased Escherichia coli, but had no effect on Salmonella counts. In conclusion, organic acid mixtures are more efficient than antibiotic growth promoter (Enramycin) in improving broiler performance and decreasing intestinal Escherichia coli and Salmonella spp., and could be successfully used to substitute antibiotic growth promoters in broiler diets. However, not all of the organic acid mixtures gave the same effect either on performance or