ABSTRACT This study evaluated the nutritional value of glycerin added to diets of weaned piglets and its effects on animal performance and urinary losses. Weaned piglets were individually housed in metabolic cages and fed diets in which a basal diet containing lactose (Gly0) was replaced by 50 (Gly50), 100 (Gly100), or 150 g kg−1 (Gly150) of glycerin; or a diet in which 100 g kg−1 of the lactose in the basal diet was replaced by glycerin (Gly100Lac0). Diets were offered for two periods of 12 days (phase I and phase II). Performance, nutrient digestibility, nitrogen retention (NR), and urinary production were measured. Digestible (DE) and metabolizable energy (ME) of glycerin were calculated using substitution method and compared to iso-nutritional diets formulated with or without glycerin. No significant differences on average daily gain, average daily feed intake, and feed conversion ratio were found. Glycerin inclusion caused a linear increase in urinary production. Piglets fed Gly100Lac0 diet had higher urinary production, compared with piglets fed Gly0. Glycerin had no significant effects on total tract apparent digestibility (TTAD) coefficients of dry matter (DM), crude protein, and gross energy (GE). Also, no significant effects were found in total tract apparent metabolizability (TTAM) coefficient of GE, NR coefficient, DE, ME, and fecal GE losses. Urinary production and GE in urine increased linearly and quadratically, respectively, with increased levels of glycerin in diets. The Gly100Lac0 diet resulted in lower DM TTAD and GE TTAM and higher GE losses in urine and feces compared with Gly0. The nutritional value of glycerin allows its inclusion at up to 100 g kg−1 in diets of weaned piglets without impairing animal performance and metabolism. Also, glycerin can replace 100 g kg−1 of lactose without impairing performance.

RESUMO: O experimento foi conduzido com o objetivo de avaliar o efeito de aditivos promotores de crescimento como alternativa ao uso de antibióticos no desempenho, na morfologia intestinal e na microbiota de leitões dos 21 aos 35 dias de idade. Um total de 160 leitões híbridos comerciais, machos castrados e fêmeas, com peso inicial de 6,10±0,709kg, foram distribuídos em delineamento inteiramente casualizado, com cinco tratamentos: Ração basal - Controle Negativo (CN); Ração basal + antibiótico (CP); Ração basal +mananoligossacarídeo (MOS); Ração basal + ácido orgânico (AO); Ração basal + mananoligossacarídeo + ácido orgânico (MOS+AO), oito repetições e quarto animais por unidade experimental. A inclusão dos aditivos não teve efeito (P>0,05) no peso médio final dos leitões. Da mesma forma, não foram observados efeitos (P>0,05) dos aditivos no consumo de ração médio diário. A conversão alimentar melhorou (P<0,01) com a inclusão dos aditivos na ração comparados com os animais alimentados com a ração CN. Não houve efeito (P>0,05) dos aditivos na morfologia do epitélio intestinal e na composição da microbiota (enterobactérias e lactobacilos). A utilização de antibiótico, probióticos, ácidos orgânicos ou de probióticos associado com ácidos orgânicos na ração melhora a conversão alimentar de leitões, dos 21 aos 34 dias de idade. Os aditivos não tiveram efeitos na morfologia intestinal e na microbiota dos leitões.

ABSTRACT: This experiment was conducted to evaluate the effect of growth promoter additives an alternative to antibiotics on performance, intestinal morphology and on microbiota of 21-to-35-day-old piglets. A total of 160 commercial crossbred piglets (males and females) with initial weight of 6.10±0.709kg were allotted in a completely randomized design with five treatments: Basal diet - Negative Control (NC); Basal diet + antibiotic (PC); Basal diet + mannanoligosaccharides (MOS); Basal diet + organic acids (OA), Basal diet + mannanoligosacharides + organic acids (MOS+OA), eight replicates and four piglets per experimental unit. The inclusion of additives in the diets had no effect (P>0.05) on the final average weight of piglets. Similarly, no effects (P<0.05) were observed on average daily feed intake and on average daily weight gain. The feed conversion improved (P<0.01) with the inclusion of additives in the diets compared to piglets fed with the NC. There was no effect (P>0.05) of the dietary additives on intestinal morphology and microbiota composition (enterobacteria and lactobacilli). Use of antibiotics, prebiotics, organic acids or prebiotics associated with organic acids in the diet improves feed conversion of piglets from 21 to 35 days of age. The additives have no major effects on piglets’ intestinal morphology and microbiota.