ABSTRACT The objective was to explore publications on the effects of genotype × environment interaction (GEI) in livestock farming. The dataset used for this analysis came from the Web of Science (WOS) database, and the search was carried out from the first article identified in the WOS database until the search date (August 17, 2023). A set of minimum parameters was defined, and then the data was processed using the VOSviewer® software. To generate visual representations in VOSviewer, fractional counting was used, in which the contribution of each article is divided proportionally based on the number of co-authors. Consequently, if an article has three authors, the weight of each author is calculated as 1/3. Brazil and the United States lead research on GEI, while India, China, and Uruguay are emerging countries on the subject. The most cited journals on GEI include the Journal of Animal Science, Journal of Dairy Science, Animal, Livestock Science, Journal of Animal Breeding and Genetics, and Revista Brasileira de Zootecnia. In Brazil, the research groups are at the forefront of publications related to GEI. Ongoing climate changes over the years have likely led to further investigations into this matter. In the Brazilian context, research groups from the São Paulo State University (UNESP), College of Agricultural and Veterinary Sciences - Jaboticabal, and the Faculty of Veterinary Medicine and Animal Science at the University of São Paulo (FZEA/USP, Campus Pirassununga) have played a prominent role in advancing this area of study. Furthermore, our bibliometric analysis revealed future trends in GEI publications, including an increasing integration of genomic information into research. (GEI farming (WOS August 17 2023. 2023 . 2023) defined VOSviewer software coauthors. coauthors co authors. authors co-authors Consequently 13 1 3 1/3 India China subject Genetics Zootecnia matter context UNESP, UNESP , (UNESP) Jaboticabal FZEA/USP, FZEAUSP FZEA USP (FZEA/USP Pirassununga study Furthermore 202 1/ (UNESP FZEA/USP 20 2

ABSTRACT The objective of this study was to evaluate the in vitro fermentation products, digestibility, gas production (GP) kinetics, and enteric greenhouse emissions (CH4 and CO2) of substrates with different forage:concentrate ratios (100F, grass hay only; 100C, concentrate mixture only, and mixture, an equal proportion of them) within non-woven fabric (NWT; 100 g/m2) or F57 (Ankom®) filter bags compared to directly dispersed in the medium (DIS), arranged in a 3 × 3 factorial arrangement. Substrates (0.5 g) were incubated using an AnkomRF GP System. Gas samples were collected during 24 and 48 h of incubation. We observed substrate × dispersion method interactions on GP at 48 h (GP48) and on in vitro organic matter digestibility (IVOMD). The GP48 and IVOMD of the 100C substrate were greatest in DIS, intermediate in NWT, and least in F57. With mixture substrate, there were no differences in GP48 and IVOMD between DIS and NWT, but they were greater than in F57. The GP48 and IVOMD were greater in NWT than in DIS and F57 when 100F was incubated. There were no dispersion method × substrate interactions on molar proportions and total volatile fatty acids. With the increase in forage:concentrate ratio incubated, there was a linear decrease in CH4 and CO2 emission relative to organic matter digested. Overall, CH4 and CO2 emissions and digestibility were lower when substrates were incubated within filter bags. The noteworthy interaction between the incubation method and substrates indicates that the ranking of these variables for substrates with differing fermentabilities changes with the dispersion method employed. products (GP kinetics CH (CH CO forageconcentrate forage 100F, F (100F only C them nonwoven non woven (NWT 10 g/m2 gm2 gm g m2 m F5 Ankom® Ankom (Ankom® , (DIS) arrangement 0.5 05 0 5 (0. System 2 4 (GP48 IVOMD. . (IVOMD) GP4 acids digested Overall employed 1 g/m (Ankom (DIS 0. (0 (GP4 (IVOMD (

ABSTRACT This study aimed to evaluate the effects of two maturity stages of whole-plant corn at harvest (32.1 or 42.5% dry matter (DM)) and a commercial microbial inoculant composed of L. buchneri and L. plantarum at concentration of 110,000 CFU/g of fresh forage (1.1 × 105 CFU/g FF) on fermentation losses, aerobic stability, chemical composition, and digestibility of starch and neutral detergent fiber (NDF). A factorial and randomized design was used (two DM contents, both with or without inoculant), with five replicates per treatment. Dry matter at harvest affected most variables, except lignin, NDF digestibility, ethanol, and lactic and acetic acids. Drier silages differed in total DM losses (−1.7%) and lactic acid bacteria (LAB) population (+1.2 log CFU/g). The use of the inoculant affected the levels of ether extract (+0.27% DM), starch (+2.9% DM), and lignin (−0.17% DM). The LAB (+1.6 log CFU/g) and yeast (−2.82% log CFU/g) populations were also influenced, as well as aerobic stability at six days. The inoculant × DM interaction was observed in the water-soluble carbohydrates content, being higher in silages with 32.1% DM and in those not inoculated for both DM. Crude protein was also higher in these silages, whether inoculated or not. Wetter silages were more prone to gas losses when inoculated (+2.5% DM) and lost more effluent when not inoculated (+4.82 kg/t FF). However, total DM losses during aerobic stability were on average 10.58% DM lower in these silages, with inoculation being preferred (6.72% DM vs 11.60% DM (control)). Under these conditions, harvesting corn for silage at 42.5% DM is indicated to obtain a more energetic silage, as noted both in the increased starch content and the reduced losses associated with fermentation. wholeplant whole plant 32.1 321 32 1 (32. 425 42 5 42.5 (DM) L 110000 110 000 110,00 CFUg CFU g 1.1 11 (1. 10 FF composition NDF. . (NDF) contents inoculant, , inoculant) treatment variables ethanol acids −1.7% 17 7 (−1.7% (LAB +1.2 12 2 (+1. CFU/g. +0.27% 027 0 27 (+0.27 DM, +2.9% 29 9 (+2.9 −0.17% 017 (−0.17 +1.6 16 6 −2.82% 282 82 (−2.82 influenced days watersoluble water soluble +2.5% 25 (+2.5 +4.82 482 4 (+4.8 kgt kg t FF. However 1058 58 10.58 6.72% 672 72 (6.72 1160 60 11.60 control. control (control)) conditions 32. 3 (32 42. (DM 11000 00 110,0 1. (1 (NDF −1.7 (−1.7 +1. (+1 +0.27 02 (+0.2 +2.9 (+2. −0.17 01 (−0.1 −2.82 28 8 (−2.8 +2.5 +4.8 48 (+4. 10.5 6.72 67 (6.7 116 11.6 (control) (3 1100 110, ( −1. (−1. +1 (+ +0.2 (+0. +2. (+2 −0.1 (−0. −2.8 (−2. +4. (+4 10. 6.7 (6. 11. (control −1 (−1 + +0. (+0 +2 −0. (−0 −2. (−2 +4 6. (6 − (− +0 −0 −2

ABSTRACT The objective of this study was to examine the physicochemical composition and sensory properties of Boursin cheese made from the milk of goats fed diets with increasing levels of cassava chips replacing corn. Eight lactating Alpine goats were distributed into two 4 × 4 Latin squares, where they were subjected to diets in which 0, 33, 66, and 100% of corn was replaced with cassava chips. The cheeses were prepared with individual milk of each goat for physicochemical, yield, and texture analyses. Sensory analysis consisted of flavor and texture appraisal by 50 untrained tasters, using the difference-from-control test and the acceptance test. The cheeses from the four treatments did not differ in their fat, protein, and total solid contents; acidity; moisture; ash; pH; yield; or the texture parameters of gumminess, cohesiveness, hardness, and chewiness. They also showed no difference in the sensory acceptance of flavor and texture, indicating that the panelists did not perceive the replacement of corn with cassava chips. squares 0 33 66 100 yield analyses 5 tasters differencefromcontrol control fat protein contents acidity moisture ash pH gumminess cohesiveness hardness chewiness 3 6 10 1

ABSTRACT This study aimed to develop and assess a deterministic mathematical model for predicting the impacts of varying sow replacement rates on the performance of farms producing weaned piglets. Initially, the influence of replacement rate on herd structure was examined using two equations, which accounted for the percentage of sows replaced (55, 45, and 35%), retention rates between parities (13, 9, and 5%), and number of last parities in the herd (6, 7, and 8). The model then estimated sow development throughout the reproductive cycle, starting with an initial weight of 140 kg at first mating and adjusting for weight gains during gestation and losses during lactation, influenced by the varying number of live-born piglets across parities. Energy requirements were calculated using the factorial method, which included maintenance, protein and fat gains, and milk production. The generated data formed various scenarios to derive productive values. These scenarios were analyzed using analysis of variance with the general linear model procedure, treating each scenario as a separate treatment. Early parities (up to P3) contributed 42% in SC-35, 51% in SC-45, and 60% in SC-55. Significant differences were noted in variables such as average parity, birth weight, feed intake during gestation, and average piglet weight gain. The developed model, incorporating replacement gilt modules, gestation, and lactation, can effectively predict herd structure by parity and assess the impact of annual sow replacement rates on the productivity of farms rearing weaned piglets. Initially equations 55, 55 (55 45 35%, 35 35% , 35%) 13, 13 (13 9 5%, 5 5% 5%) 6, 6 (6 7 8. 8 . 8) cycle 14 lactation liveborn live born method maintenance production values procedure treatment up P3 P 42 SC35, SC35 SC 35, SC-35 51 SC45, SC45 SC-45 60 SC55. SC55 55. SC-55 gain modules (5 4 3 1 (1 ( SC3 SC-3 SC4 SC-4 SC5 SC-5 SC-

ABSTRACT The objective of this study was to assess the effects of high-concentrate diets with and without the inclusion of soybean hull (SH; 0 or 500.8 g/kg) plus corn (whole or ground) on the performance, morphometric traits, and nutritional and metabolic parameters of crossbred dairy calves. We also aimed to assess the costs associated with the experimental diets employed. Thirty-six male calves with an average weight of 89±18.6 kg and age of 3.5 months were allocated to four treatments, with nine replicates of one calf/pen, in a completely randomized experimental design for 198 days. The inclusion of the SH and the physical form of corn did not influence animal performance or morphometric measurements; however, SH inclusion increased the digestibility of neutral detergent fiber and the intakes of dry matter and neutral detergent fiber, but did not affect total digestible nutrient intake. The physical form of corn did not influence nutrient intake or digestibility, which resulted in similar performance across the animals. Blood glucose levels as well as alkaline phosphatase and creatinine remained elevated regardless of the diet. The use of SH reduced the total plasma cholesterol content, and there was an interaction between the physical form of corn and SH inclusion in relation to creatinine levels, which were higher when using diets with whole corn and SH. Although the inclusion of up to 500.8 g/kg of SH in the diet reduces feed efficiency, its use decreases the cost per kilogram of weight gain. Dairy calves can exhibit satisfactory production performance when fed alternative ingredients such as whole corn or SH, which have a lower cost than ground corn, traditionally used in diet formulations. highconcentrate high concentrate (SH 5008 500 8 500. gkg g traits employed Thirtysix Thirty six 89186 89 18 6 89±18. 35 3 5 3. treatments calfpen calf pen calf/pen 19 days measurements however animals content efficiency gain formulations 50 8918 1 89±18 891 89±1 89±

ABSTRACT Two experiments were conducted to assess the impact of an enzyme complex (EC) on the metabolizability coefficients of dry matter (MCDM), crude protein (MCCP), and ether extract (MCEE) and on the nitrogen-corrected apparent metabolizable energy (AMEn) of corn gluten meal, soybean protein concentrate, dried bovine plasma, and poultry offal meal. Additionally, the experiments aimed to evaluate how EC affected broiler performance. In experiment I, 720 day-old Cobb 500® broilers were assigned to a completely randomized design using a 4 × 2 factorial arrangement. The main factors considered were the feedstuff (corn gluten meal, soybean protein concentrate, dried bovine plasma, and poultry offal meal) and the presence or absence of EC. The broilers were housed in 45 pens, using five replicates, with ten birds in the pre-starter phase and six birds in the starter phase. This design resulted in eight treatment groups, including one reference diet group. In experiment II, 1140 day-old Cobb 500® chicks were allotted in a completely randomized design, employing a 4 × 2 factorial arrangement, with the same main factors as in experiment I. Birds were housed in 48 pens, using six replicates/30 birds, yielding eight treatments. The use of the EC did not lead to improvements in digestibility of the feedstuffs. However, the addition of EC resulted in enhanced body weight gain and improved feed conversion ratios across all phases of broiler growth. Enzyme complex inclusion did not affect feed intake. While the EC did not enhance the metabolizability of nutrients in feedstuffs individually, broilers fed diets containing these feedstuffs and supplemented with EC exhibited improved performance at 42 days of age. This suggests that the impact of the EC varies depending on whether it is observed at the feedstuff or diet level. (EC MCDM, MCDM , (MCDM) MCCP, MCCP (MCCP) MCEE (MCEE nitrogencorrected nitrogen corrected AMEn (AMEn meal concentrate plasma Additionally I 72 dayold day old 500 arrangement pens replicates prestarter pre groups group II 114 replicates30 30 replicates/3 treatments However growth intake individually age level (MCDM (MCCP 7 50 11 replicates3 3 replicates/ 5 1

ABSTRACT This research aimed to evaluate the influence of a commercial prebiotic in different concentrations upon several parameters. To carry out the experiment, 640 male one-day-old broiler chicks were distributed in four treatments (0, 0.5, 1.0, and 1.5 kg/ton of yeast cell wall) with eight replicates of 20 birds per experimental unit, in randomized blocks. Prebiotic effects were assessed on performance, carcass yield and prime cuts, in addition to the litter quality (its content of nitrogen and phosphorus). There were significant improvements for weight gain and feed conversion ratio in experimental growth periods. However, prebiotic level at 1.0 kg/ton is enough to provide improvement in performance and similar yield parameters than the control group. Also, 1.5 kg/ton prebiotic inclusion in the diet promotes environmental benefits by reducing the phosphorus amount in the litter by 51%. Above 1.0 kg/ton prebiotic addition in broiler diets can be safely recommended, because it promotes both performance and environmental benefits. experiment 64 onedayold one day old 0, 0 (0 05 5 0.5 10 1 15 1. kgton kg ton wall 2 unit blocks cuts its phosphorus. . phosphorus) periods However group Also 51 51% recommended 6 ( 0.

ABSTRACT This trial was designed to evaluate the effect of processing method of rehydrated corn grain silage (RCGS) on feed intake, performance, carcass traits, feeding behavior, rumen morphology, and blood metabolites of cattle in the finishing phase. Thirty-eight F1 Angus × Nellore bulls (365±22 kg) raised under grazing conditions were housed in individual pens (2 × 4 m) for the feeding trial. At the end of the adaptation period, animals were weighed after a 16-h fast, blocked by shrunk body weight, and randomly assigned to one of two dietary treatments: GRC, consisting of RCGS that was ground before ensiling using a hammer mill with a uniform 8-mm screen (1.52 mm geometric mean particle size); and RRC, consisting of RCGS that was rolled before ensiling in a roller mill mounted in a bagging machine (2.18 mm geometric mean particle size). Diet ingredients were mixed manually twice daily, at 09:00 and 15:00 h, and offered as total mixed rations in amounts approximately 50 g/kg in excess of daily intake. The experimental diets contained a forage:concentrate ratio of 130:870 g/kg, with 644 g/kg of RCGS. The GRC resulted in greater daily variation in dry matter intake, total-tract digestibility (dry and organic matter), fecal pH, rumen papillae width, and lower first meal duration, meal length, fecal starch, and rumen papillae height than the RRC. However, grinding or rolling RCGS did not affect dry matter intake, growth performance, carcass traits, or health (liver abscesses, ruminitis, serum D-lactate) of finishing beef cattle. Therefore, the processing equipment to make RCGS might be preferable based on equipment availability, milling yield, energy consumption, and diet composition. (RCGS intake performance traits behavior morphology phase Thirtyeight Thirty eight F 365±22 36522 365 22 (365±2 kg 2 ( m period 16h h 16 fast weight treatments 8mm 8 1.52 152 1 52 (1.5 size size) RRC 2.18 218 18 (2.1 size. . 0900 09 00 09:0 1500 15 15:0 5 gkg g forageconcentrate forage concentrate 130870 130 870 130:87 64 totaltract tract matter, , matter) pH width duration length starch However liver abscesses ruminitis Dlactate D lactate D-lactate Therefore availability yield consumption composition 365±2 3652 36 (365± 1.5 (1. 2.1 21 (2. 090 0 09: 150 15: 13087 13 87 130:8 6 365± 3 (365 1. (1 2. 1308 130: (36 (3

ABSTRACT The objective of this study was to assess the genetic structure and diversity of six Santa Inês sheep flocks from the Central-Northern Brazil. A panel of 20 highly polymorphic and informative microsatellite loci was selected and amplified. The following parameters were obtained: overall mean of number of alleles = 15.4; expected heterozygosity (He) = 0.89; polymorphism information content (PIC) = 0.88; discriminatory capacity = 0.95; combined probability of identity = 1.50 × 10−34; and probability of exclusion = 1.00. The flocks with the lowest and the highest degrees of genetic variability were Farm 6 (He = 0.70, PIC = 0.653, and allelic richness [Ar] = 3.76) and Farm 1 (He = 0.89, PIC = 0.882, and Ar = 4.39), respectively. Indications of genetic bottleneck were observed in all flocks, as well as moderate genetic differentiation, with FST = 0.053, RST = 0.096, and Dest = 0.169. The migration rate in all flocks was high, with a trend towards Farm 1. This finding was not in agreement with the substructure found with the Bayesian admixture analysis and corroborated the array obtained with the principal component analysis and the clustering analysis. The results revealed moderate structuring and high genetic diversity in the flocks. However, management strategies should be reviewed, as evidence of bottleneck and genetic erosion was observed. CentralNorthern Central Northern Brazil 2 amplified 15.4 154 15 4 He 0.89 089 0 89 (PIC 0.88 088 88 0.95 095 95 150 50 1.5 10−34 1034 10 34 100 00 1.00 070 70 0.70 0653 653 0.653 [Ar 3.76 376 3 76 0882 882 0.882 4.39, 439 4.39 , 39 4.39) respectively differentiation 0053 053 0.053 0096 096 0.096 0169 169 0.169 However reviewed 15. 0.8 08 8 0.9 09 9 5 10−3 103 1.0 07 7 0.7 065 65 0.65 3.7 37 43 4.3 005 05 0.05 009 0.09 016 16 0.16 0. 10− 06 0.6 3. 4. 0.0 01 0.1

ABSTRACT This study aimed to investigate the effects of xylanase (Xyl) individually or in combination with B. subtilis and B. licheniformis associated or not with yeast cell wall in pig diets with a reduction of 100 kcal/kg of metabolizable energy (ME) content. Pig performance, bone parameters, intestinal morphometry, and bioeconomic indices were evaluated. A total of 75 pigs (25 females and 50 barrows; 25.02±3.21 kg) obtained from crossing Large White × Landrace were used. The experimental design consisted of randomized blocks, with five treatments and five blocks, totaling 25 experimental units subjected to treatments: basal diet (B); basal diet with reduction of 100 kcal/kg of ME (BEM); BEM with supplementation of xylanase (0.01%; BX); BX with supplementation of direct-fed microbials (composed of B. subtilis and B. licheniformis; 0.02%; BXM); and BX supplemented with 0.10% of symbiotic (which includes B. subtilis, B. licheniformis, and yeast cell wall; BXS). There were no differences in bone parameters. The BEM diet resulted in a lower villus height:crypt depth ratio in the jejunum than that seen upon using the BXS diet as feed. In the first period, pigs fed BEM diet had a 12% higher average daily feed intake than those fed the BXM diet. There were no differences in the pig performance during the second period. Over the total period, pigs fed BEM diet had greater FCR compared with pigs fed BXM diet. The inclusion of feed additives in diets with reduced ME content contributes to the maintenance of performance and characteristics of the metacarpus and jejunum of growing pigs and provides better bioeconomic indices. Xyl (Xyl B 10 kcalkg kcal kg (ME parameters morphometry evaluated 7 (2 5 barrows 2502321 02 3 21 25.02±3.2 used blocks 2 (B) (BEM) 0.01% 001 0 01 (0.01% BX) directfed direct composed 0.02% 002 BXM) 010 0.10 which BXS. . BXS) heightcrypt height crypt period 12 1 ( 250232 25.02±3. (B (BEM 0.01 00 (0.01 0.02 0.1 25023 25.02±3 0.0 (0.0 0. 2502 25.02± (0. 250 25.02 (0 25.0 25.

ABSTRACT The objective of this study was to estimate the genetic parameters and predict selection of genetic gains and genetic diversity of 12 Andropogon lateralis ecotypes collected in the State of Rio Grande do Sul, Brazil. To estimate genetic parameters and predict selection gains, the REML/BLUP technique was applied. Genetic diversity among the ecotypes was evaluated by two clustering methods (optimization and hierarchical) and principal component (PC) analysis, the latter method also used to discard variables. The genetic parameters studied showed high potential for selection of important agronomic forage traits for livestock production. Results showed that the 12 A. lateralis Nees ecotypes exhibited high genetic variability for the studied forage characters and indicated parental prosperity for crosses within the genetic breeding program. Principal component analysis showed that number of total vegetative tillers, leaf:stem ratio, number of reproductive tillers, and leaf dry matter yield accounted for 80.6% of the observed variation in PC1. These variables are important characteristics for quantifying the dry matter production and nutritional value of forage plants, and they can help to discriminate amongst ecotypes. Ecotypes sourced from the Pelotas, Piratini, Passo Fundo, Bagé, and Montenegro regions showed superior forage production when evaluated by the BLUP methodology. Therefore, this group was identified as the most suitable for selection and crossing purposes. Tocher’s cluster analysis grouped the ecotypes into five divergent groups. Principal component and UPGMA hierarchical methods were also efficient at separating the ecotypes. 1 Sul Brazil REMLBLUP REML applied optimization PC (PC A program tillers leafstem stem ratio 806 80 6 80.6 PC1 plants Pelotas Piratini Fundo Bagé methodology Therefore purposes Tochers Tocher s groups 8 80.

ABSTRACT In this study, a mixture of estradiol benzoate, progesterone, and testosterone propionate was injected into Diannan small-ear sows to induce estrus. The 16S rRNA technology was used to comparatively analyze the differences in fecal microbial composition and diversity between induced and spontaneous estrus in Diannan small-ear sows. The most abundant phylum in the sows in estrus were Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria. There was a significant negative correlation between Firmicutes and Bacteroide and a significant positive correlation between Bacteroides and Bifidobacterium. The relative abundance of Stenotrophomonas, Neisseria, Anaerofustis, and Terrisporobacter in the sows during induced estrus was significantly higher than that during spontaneous estrus. Taken together, induced estrus affects the relative abundance of specific microbes in the feces of Diannan small-ear sows, but it does not affect the overall composition and diversity. These results provide fundamental knowledge about the gut microbiota of sows with induced estrus. study benzoate progesterone smallear small ear S Bacteroidetes Actinobacteria Proteobacteria Bifidobacterium Stenotrophomonas Neisseria Anaerofustis together

ABSTRACT This study aimed to analyze the economic viability of the implementation of a mechanized harvesting of broilers where the activity is carried out entirely manually. The viability indicators used were net present value (NPV), net future value (NFV), net uniform value (NUV), discounted payback (DP), and internal rate of return (IRR). Scenario analysis, sensitivity, and Monte Carlo simulation were performed in the present study. The results showed that the initial investment was US$ 1,868,302.76. The average price paid by the slaughterhouse to third-party manual harvesting companies was US$ 18.17 per thousand broilers, which was converted into revenue in the cash flow of the project. The cash flow result was positive at US$ 22,256.14 over the entire study period considering a daily catch of 144 thousand broilers. The results of the economic viability analysis were NPV of US$ 64,786.23, NFV of US$ 333,382.11, NUV of US$ 735.19, DP of 13.82 years, IRR of 0.965 monthly, and modified IRR of 0.933 monthly. These values prove the economic viability of implementing the project considering the market conditions at the time of the study. The analysis of scenarios showed great sensitivity to the exchange rate and the price of fuels. The Monte Carlo simulation highlighted a moderate risk of negative NPV, emphasizing the importance of considering this variable when making decisions. Despite these challenges, the potential benefits of mechanized harvesting, such as increased efficiency and reduced labor costs, make it a promising alternative to manual harvesting, even for small to medium-sized poultry industries. manually , (NPV) NFV, (NFV) NUV, (NUV) DP, (DP) IRR. . (IRR) US 186830276 1 868 302 76 1,868,302.76 thirdparty third party 1817 18 17 18.1 2225614 22 256 14 22,256.1 6478623 64 786 23 64,786.23 33338211 333 382 11 333,382.11 73519 735 19 735.19 1382 13 82 13.8 years 0965 0 965 0.96 monthly 0933 933 0.93 fuels decisions challenges costs mediumsized medium sized industries (NPV (NFV (NUV (DP (IRR 18683027 86 30 7 1,868,302.7 181 18. 222561 2 25 22,256. 647862 6 78 64,786.2 3333821 33 38 333,382.1 7351 73 735.1 138 8 13. 096 96 0.9 093 93 1868302 3 1,868,302. 22256 22,256 64786 64,786. 333382 333,382. 735. 09 9 0. 186830 1,868,302 2225 22,25 6478 64,786 33338 333,382 18683 1,868,30 222 22,2 647 64,78 3333 333,38 1868 1,868,3 22, 64,7 333,3 186 1,868, 64, 333, 1,868 1,86 1,8 1,

ABSTRACT The objective of this study was to evaluate the effects of prebiotics, alone and in combination with antibiotics, on broiler performance, carcass yield, intestinal permeability, and intestinal morphometry. A total of 1440 day-old male Cobb 500 chicks were distributed in a completely randomized design, with four treatments and 10 replications per treatment. The treatments used were a basal diet without prebiotics and antibiotics (BD), a basal diet with antibiotics (AB), a basal diet with prebiotics (PRE), and a basal diet with antibiotics and prebiotics (AB+PRE). To perform the treatment, the antibiotic zinc bacitracin and a prebiotic of S. cerevisiae-derived mannan-oligosaccharides and beta-glucans were used. The treatments did not affect the performance of birds from 1 to 7 and 1 to 21 days of age. From 1 to 35 and 1 to 42 days, birds fed the AB+PRE treatment had higher feed intake than those fed the AB treatment. From 1 to 35 days, birds fed the AB+PRE treatment showed a worse feed conversion ratio. However, there was no difference in carcass yield between treatments. A higher number of goblet cells was observed in the duodenum and ileum of birds fed AB+PRE, but lower counts were obtained in birds fed AB. Intestinal histomorphometry displayed similar responses between both ages regarding antibiotic and prebiotic treatments, except in the ileum at 42 days, in which the antibiotic elicited a better response. Intestinal permeability analysis showed no significant difference between diets. The use of prebiotics, alone or in combination with antibiotics, does not improve the performance of broilers. morphometry 144 dayold day old 50 design BD, BD , (BD) AB, (AB) PRE, PRE (PRE) AB+PRE. ABPRE . (AB+PRE) S cerevisiaederived cerevisiae derived mannanoligosaccharides mannan oligosaccharides betaglucans beta glucans 2 age 3 4 ratio However response diets broilers 14 5 (BD (AB (PRE (AB+PRE