Characterization of the nutritional interactions between organic acids and inorganic bases in the pig and chick

Effect of probiotic-, bacteriophage-, or organic acid-supplemented feeds or fermented soybean meal on the growth performance, acute-phase response, and bacterial shedding of grower pigs challenged with Salmonella enterica serotype Typhimurium

A 28-d experiment evaluated the growth performance, acute-phase response, and bacterial shedding patterns in pigs (n = 108; initially, 38.7 ± 6.7 kg) fed 6 treatment diets, including a control diet with no antimicrobial agents (CON), a positive control diet containing chlortetracycline, 100 mg/kg (CT), a diet containing anti-Salmonella Typhimurium bacteriophage, 3 × 10(9) plaque-forming units/kg of feed (ASB), Lactobacillus plantarum CJLP56, 6.5 × 10(8) cfu/kg of feed (LP), 0.2% microencapsulated organic acids (MOA), or 5% fermented soybean meal (FSM). Pigs were fed the diets for 2 wk before and 2 wk after challenging orally with Salmonella enterica serotype Typhimurium (SalT). Before bacterial challenge, ADFI was similar in all groups. After SalT challenge, ADFI of CON pigs was less (P < 0.05) than all other groups. Before challenge, pigs on MOA, FSM, and CT diets had greater (P < 0.05) ADG and G:F than CON pigs. After challenge (wk 3 to 4) and during the overall experimental period (wk 1 to 4), ADG of all treatment groups and G:F of all treatment groups except the LP group were greater (P < 0.05) than those of CON pigs. Relative to all other treatments, CON and LP pigs had greater (P < 0.05) bacterial shedding scores on d 7 after SalT challenge. At d 14 postchallenge, shedding scores declined (P < 0.05) in all treatment groups compared with CON pigs. Serum haptoglobin for all treatment groups increased from d 0 concentrations on d 6 postchallenge and declined to prechallenge concentrations on d 13 (P < 0.05). Circulating IGF-I concentrations declined from 2 to 6 d postchallenge and increased again by d 13 in ASB and LP groups, did not decline in FSM and CT groups, and continuously declined through d 13 in CON and LP groups (P < 0.05). However, in MOA group, IGF-I concentrations declined from preinfection concentrations on d 2, increased on d 4, and declined again until d 13 (P < 0.05). The serum concentrations of the cytokines IL-6 and IL-1β were not generally affected by SalT challenge. In conclusion, acute infection of growing pigs with SalT was associated with short-term febrile responses in most pigs and reductions in ADFI and ADG of CON pigs. Compared with the CON diet, ASB, FSM, and MOA diets had a similar benefit to the antibiotic-supplemented diet in improving the performance of growing pigs, especially after bacterial challenge. However, further work needs to be done to better understand their mode of action in this class of pigs.

Organic acids for performance enhancement in pig diets

Organic acids and their salts appear to be potential alternatives to prophylactic in-feed antibiotics and growth promoters in order to improve the performance of weaned piglets, fattening pigs and reproductive sows, although their growth-promoting effects are generally less than that of antibiotics. Based on an analysis of published data, the growth-promoting effect of formates, fumarates and citrates did not differ in weaned piglets. In fattening pigs, formates were the most effective followed by fumarates, whereas propionates did not improve growth performance. These acids improved the feedgain ratio of both weaned piglets and fattening pigs. In weaned piglets, the growth-promoting effects of dietary organic acids appear to depend greatly on their influence on feed intake. In sows, organic acids may have anti-agalactia properties. Successful application of organic acids in the diets for pigs requires an understanding of their modes of action. It is generally considered that dietary organic acids or their salts lower gastric pH, resulting in increased activity of proteolytic enzymes and gastric retention time, and thus improved protein digestion. Reduced gastric pH and increased retention time have been difficult to demonstrate, whereas improved apparent ileal digestibilities of protein and amino acids have been observed with growing pigs, but not in weaned piglets. Organic acids may influence mucosal morphology, as well as stimulate pancreatic secretions, and they also serve as substrates in intermediary metabolism. These may further contribute to improved digestion, absorption and retention of many dietary nutrients. Organic acid supplementation reduces dietary buffering capacity, which is expected to slow down the proliferation and|or colonization of undesirable microbes, e.g. Escherichia coli, in the gastro-ileal region. However, reduced scouring has been observed in only a few studies. As performance responses to dietary organic acids in pigs often varies, more specific studies are necessary to elucidate an explanation.

Ácido fumárico e sua combinação com os ácidos butírico ou fórmico em dietas de leitões recém desmamados

Avaliaram-se o desempenho e as características morfológicas e morfométricas do intestino delgado de 210 leitões, desmamados aos 15 dias de idade, com peso médio inicial 4,04±0,66kg, em dois períodos experimentais (15-30 e 15-36 dias de idade). O delineamento experimental foi em blocos ao acaso, com sete tratamentos (T1: ração-controle sem adição de acidificante; T2: ração-controle + 0,5% de ácido fumárico; T3: ração-controle + 1,0% de ácido fumárico; T4: ração-controle + 0,5% de ácido fumárico +0,1% de ácido butírico; T5: ração-controle + 0,5% de ácido fumárico + 0,5% de ácido fórmico; T6: ração-controle + 1,0% de ácido fumárico + 0,1% de ácido butírico e T7: ração-controle + 1,0% de ácido fumárico +0,5% de ácido fórmico), cinco repetições e seis animais por unidade experimental. O peso dos leitões aos 30 dias de idade não foi influenciado pelos tratamentos, mas houve efeito significativo de tratamento sobre ganho de peso e consumo alimentar diário no período de 15-30 dias de idade, com maior desempenho para os leitões alimentados com dietas suplementadas com ácido fumárico. Não houve efeito significativo dos tratamentos sobre o peso médio aos 36 dias, o ganho de peso, o consumo diário e a conversão alimentar dos leitões de 15 a 36 dias de idade. Houve diferença entre tratamentos para a altura do epitélio do duodeno, porém não houve diferença em relação à do jejuno e à do íleo. As eletromicrografias do duodeno dos leitões alimentados com as diferentes dietas experimentais revelaram vilosidades com características normais.