The effect of organic acids as an alternative to antibiotics on the performance of broiler chickens was evaluated by meta-analysis, identifying and quantifying the main factors that influence results. A total of 51,960 broilers from 121 articles published between 1991 and 2016 were used. Interactions of additives [non-supplemented group (control), organic acids, and growth promoter antibiotics] with microbial challenge (with or without inoculation of pathogenic microorganisms) were studied on performance variables. Moreover, the effects of organic acids, used individually or in blends, were evaluated. Relative values of average daily gain (ADG) and average daily feed intake (ADFI) were obtained in relation to control: ΔADG and ΔADFI, respectively. Analysis of variance-covariance revealed lower ADG with organic acids when compared to antibiotics (P < 0.05). There was a significant interaction between the additives and the challenge on feed conversion ratio (FCR) (P < 0.01) and on viability (P < 0.05). Without challenge, organic acids improved broilers’ FCR (P < 0.01), presenting results similar to antibiotics (P > 0.05). Under challenge, the organic acids were again effective on FCR (−5.67% in relation to control, P < 0.05), but they did not match antibiotics (−13.40% in relation to control, P < 0.01). Viability was improved only under challenge conditions, and only by antibiotics (+4.39% in relation to control, P < 0.05). ADG (P < 0.05) and FCR (P < 0.01) were increased by blends of organic acids, but not by the organic acids used alone (P > 0.05). ADFI and production factor were not influenced by the treatments (P > 0.05). ΔADFI of organic-acid supplemented group showed a linear influence on ΔADG, which increases 0.64% at every 1% increase in ΔADFI. In conclusion, organic acids can be utilized as performance enhancing, but the results are lower than those found with antibiotics, particularly under microbial challenge. The blends of organic acids provide better results than the utilization of one organic acid alone.

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Three experiments with a 2 × 2 × 2 factorial arrangement were conducted to evaluate maize-based diets for broilers containing different lipid sources [soybean oil (S) or beef tallow (T)] supplemented with or without lysophospholipids and organic acids on nutrient balance (Experiment I, evaluation period of 10-14 d), on liver concentration of fat-soluble vitamins, on jejunal microbiota (Experiment II, sampling at d 14) and on performance (Experiment III, accumulated periods of 1-14, 1-21 and 1-42 d). A total of 1344 male chicks were used. In each experiment, the birds were allotted in a completely randomised design with 8 replications. The lysophospholipids were mainly composed of lysolecithins and the organic acids blend was constituted by lactic (40%), acetic (7%) and butyric acids (1%). An interaction between lipid sources and lysophospholipids was observed on faecal apparent digestibility of lipid (ADL), which improved with lysophospholipids addition in T diets. Broilers fed on S had higher ADL and faecal apparent digestibility of nitrogen-corrected gross energy (ADGE). It was not possible to demonstrate a significant treatment effect on the liver concentration of vitamins A and E, even with the differences in fatty acid profile between S and T. Enterobacteria values were below the detection threshold. Lysophospholipid supplementation reduced gram-positive cocci in T-fed birds. S diets promoted lower total anaerobe counts compared with T diets, independent of additives. S diets increased BW gain and feed:gain ratio in all evaluation periods. Lysophospholipids and organic acids improved feed:gain ratio at 1-21 d in T diets. Furthermore, main effects were observed for lysophospholipids and organic acids at 1-42 d, which increased BW gain and improved feed:gain ratio, respectively. No positive interactions between additives were found.

Two assays were conducted to evaluate nutritive value of canola meal (CM) fed to broiler chicks without or with a multi-carbohydrase (MC) preparation (700 U α-galactosidase, 2,200 U galactomannanase, 30,000 U xylanase, and 22,000 U β-glucanase per kg of diet) and phytase (Phy, 500 FTU per kg of diet). Assay 1 determined apparent total tract digestibility (ATTD) of nutrients and metabolizable energy (AME) by the difference method. Assay 2 determined apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of amino acids by the index method. Two reference diets (RD) - an 85% corn based and a 5% casein-cornstarch diet fortified with vitamins and minerals - were made for assays 1 and 2, respectively. For each assay, the test diets were made by mixing RD and CM 7:3 wt/wt basis and fed without or with MC or Phy or combination. A total of 245 day-old male broilers (Cobb 500) was allocated to 5 treatments to give 7 replicates (7 birds/cage). The birds were fed a commercial diet from day zero to 10 followed by assay 1 fed from d 11 to 18 and assay 2 fed from d 19 to 21. Excreta samples were collected on d 15 to18, and all birds were slaughtered on d 21 for ileal digesta. There was an interaction (P < 0.05) between MC and Phy on ATTD of DM, N, and P. There was no interaction (P > 0.05) between MC and Phy on AMEn; however, MC and Phy individually improved AMEn retention. Enzymes interacted (P < 0.05) on SID of Arg, His, Leu, Met, Thr, Ala, Asp, Gln, and Gly. In this context, feeding a combination of MC and Phy resulted in higher (P < 0.05) SID of Arg, His, Met, and Thr relative to single activity or control. Both enzymes improved (P < 0.05) SID of Lys independently. The combination of carbohydrase and Phy may be an effective strategy to improve amino acid utilization in CM for poultry.

Organic acids are used as feed additives to promote growth of weaned piglets since they prevent the occurrence of diarrhea. Thus, performance and digestibility assays were conducted and economic viability of diets was evaluated. In the performance assays, 64 hybrid piglets weaned with a mean weight of 5.87±0.31kg were divided in a randomized block design consisting of 4 treatments, 8 repetitions and 2 piglets per experimental unit (1 castrated male and 1 female). In the digestibility assay, 24 castrated male hybrid piglets with a mean weight of 8.21±0.79kg were individually assigned to 4 treatments and 6 repetitions. The treatments in the two assays were as follows: control, basal diet without addition of an acidifier; blend: inclusion of 0.5% of a mixture of organic acids; butyrate: inclusion of 0.1% of sodium butyrate; blend+butyrate: inclusion of 0.5% of a mixture of organic acids and 0.1% sodium butyrate. There was no effect (P>0.05) of the acidifiers on animal performance during the period studied. Organic acids exerted no effect (P>0.05) on the apparent digestibility coefficients of nutrients. Diets supplemented with sodium butyrate had an economic advantage for the period of 10-24 days. No episode of diarrhea was observed. This study demonstrated no effect of acidifier feed additives as growth promoters in complex diets for weaned piglets.Keywords: acidifiers, additives, digestibility, performance, pigs RESUMO Ácidos orgânicos são utilizados como aditivos promotores de desempenho em leitões, pois podem prevenir a ocorrência de diarreias. Para tanto, foram conduzidos ensaios de desempenho, digestibilidade, e foi avaliada a viabilidade econômica das dietas. No desempenho, foram utilizados 64 leitões híbridos desmamados, com peso médio de 5,87±0,31kg, distribuídos em um delineamento em blocos ao acaso, com quatro tratamentos, oito repetições e dois leitões por unidade experimental (sendo um macho castrado e uma fêmea

Protein sources from cereals are used in broiler diets, usually in order to reduce feeding costs. However, their efficient use in poultry diets is limited by the level of fiber whose compounds are resistant to digestion in the small intestine; due to this sugars are not digested by endogenous poultry enzymes. The aim of this study was to determine the effect of multi-carbohydrase (MC) and phytase (Phy) on the total retention of nutrients, retention of apparent metabolizable energy corrected for nitrogen (AMEN) (trial 1) and apparent and standardized ileal digestibility of amino acids (trial 2) of rice bran (RB). A total of 245-day-old male broilers (Cobb 500) was distributed at 21-day-old in a completely randomized design in a 2 × 2 + 1 (0 and 200 mg/kg MC; 0 and 50 mg/kg Phy, and basal diet – BD) factorial arrangement of treatments, to give seven replicates and seven birds per replicate. The BD based on corn (trial 1) and cornstarch and casein (trial 2) was used only to determine the coefficients of retention of nutrients and energy, and coefficients of digestibility of amino acids of the RB. The test diets were made by mixing BD and RB 7 : 3 wt/wt basis. There was interaction (P<0.05) between MC × Phy for DM, nitrogen and AMEN, retention and no interaction (P>0.05) for ash, calcium, phosphorous and NDF was observed. Enzymes interacted (P<0.05) on standardized ileal digestibility of arginine, histidine, leucine, methionine, phenylalanine, threonine, valine, aspartic acid, glutamic acid, proline and serine. Dietary combination of MC and Phy resulted in higher (P<0.05) standardized digestibility of arginine, histidine, methionine and threonine relative to single enzyme supplementation or control diet without enzymes. Enzyme isolated inclusions in the diets improved (P<0.05) standardized digestibility of methionine. The supplementation of carbohydrases and Phy in RB will improve the nitrogen, energy and amino acids utilization for broiler chickens.

Resumo -O objetivo deste trabalho foi avaliar o valor nutricional e energético de subprodutos do trigo, em dietas para suínos em crescimento, e obter equações de predição da energia metabolizável. Foram utilizados 36 suínos machos, castrados, alojados em gaiolas metabólicas individuais. Realizou-se a coleta total de fezes e urina em dois períodos de dez dias: cinco para adaptação e cinco para coleta. Utilizou-se o delineamento de blocos ao acaso, tendo-se considerado o período de coleta como bloco, com seis tratamentos e seis repetições. A dieta referência foi substituída em 30% por um dos subprodutos testados: farinheta, farelo fino, farelo de trigo, farelo grosso e farelo grosso moído; este último usado para avaliar a influência da granulometria na digestibilidade. A fibra bruta foi a variável que proporcionou a melhor estimativa da energia metabolizável. O farelo fino foi superior em energia digestível e metabolizável, em comparação ao farelo grosso moído. O farelo grosso moído apresentou os menores coeficientes de digestibilidade, e a diminuição de seu diâmetro geométrico médio não aumentou a digestibilidade dos nutrientes e da energia. Entre os subprodutos avaliados, a farinheta apresenta maior energia digestível, energia metabolizável e proteína digestível, o que mostra elevado potencial para utilização em dietas para suínos em crescimento.Termos para indexação: alimentos alternativos, digestibilidade, fibra, granulometria, metabolizabilidade. Nutritional value and metabolizable energy of wheat by-products used for feeding growing pigsAbstract -The objective of this work was to evaluate nutritional and energy values of wheat by-products in diets for growing pigs, and to obtain prediction equations for metabolizable energy. Thirty-six male pigs were housed in individual metabolic cages. Total collection of feces and urine was carried out in two periods of ten days: five days for adaptation and five days for collection. A randomized complete block design was used, considering the sampling period as a block, with six treatments and six replicates. The reference diet was replaced by 30% of one of the tested by-products: wheat middlings, fine wheat bran, common wheat bran, coarse wheat bran, and ground coarse wheat bran; the latter was used to evaluate the influence of particle size on digestibility. Crude fiber was the variable that provided the best estimate of metabolizable energy. Fine wheat bran was superior in terms of digestible and metabolizable energy, when compared to coarse wheat bran. Ground coarse wheat bran showed lower digestibility coefficients, and the reduction in its average geometric diameter did not increase nutrient availability. Among the evaluated by-products, wheat middlings have higher digestible energy, metabolizable energy, and digestible protein, showing high potential use in diets for growing pigs.

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