ABSTRACT
Benzoic acid (BA) and essential oils (EOs) (thymol, 2-methoxyphenol, eugenol, piperine, and curcumin) are being studied to minimize the impairment of gastrointestinal functions in weanling piglets. This study evaluates the effects of combining BA and EO on the performance and intestinal health of piglets challenged with E. coli F4 (1 mL, 106 CFU/mL). In total, 270 weaned piglets were used in a randomized block design with six treatments: positive control, with 40 mg/kg colistin (PC); negative control, without the growth promoter (NC); negative control +5 g/kg benzoic acid (BA); negative control +2 g/kg combination of BA+EO (BA+EO2); negative control +3 g/kg combination of BA+EO (BA+EO3); negative control +4 g/kg combination of BA+EO (BA+EO4). BA+EO3 presented a greater average daily gain (ADG) (p = 0.0013) and better feed-to-gain ratio (p = 0.0138), compared to NC, from 21 to 35 days age. For the total period, BA, BA+EO3, and BA+EO4 were similar to PC and superior to NC for ADG (p = 0.0002) and final body weight (BW) (p = 0.0002). No difference (p > 0.05) was verified for diarrhea, microbial population, production of volatile fatty acids, pH, weight of organs, cellular proliferation, and cholecystokinin count. NC and BA+EO4 resulted in a higher villus height in the jejunum (p = 0.0120) compared to BA+EO3. The use of BA or the combination of BA and EO at 3 g/kg provides improved performance, aside from being an economically viable alternative to replace colistin.
ABSTRACT
A total of 224 weaned pigs (DanBred sows x PIC 337 sires) with an average body weight (BW) of 6.37 ± 0.34 kg (21 days of age) were used to evaluate how different levels of benzoic acid fed to weaning pigs orally inoculated with Escherichia coli (K88+ ) affected the nursing and grow-finishing performance, the physicochemical properties of the intestine, the volatile fatty acid concentration in the caecum and the incidence of diarrhoea. Pigs were randomly allocated in an experimental design of randomized blocks in a 4 × 2 factorial design, and they were administered four levels of benzoic acid (0.00%, 0.25%, 0.50% and 0.75%) and inoculated (or not) in two consecutive days with 1 ml solution containing 106 CFU/ml of E. coli (K88+ ). Seven replicates (pens) per treatment were used, and four animals were kept per pen. Supplementation with 0.75% benzoic acid promoted better performance (p < 0.05) in the nursery phase as well as in the subsequent phases until slaughter, and it decreased the incidence of diarrhoea in piglets (p < 0.05). In the piglets fed the benzoic acid diet, the villus height in the jejunum and ileum was greater until 42 days of life (p < 0.05), the crypt depth was decreased in the caecum (p < 0.05), and the butyric acid concentration was increased in the caecal content tendencially (p = 0.0708). In conclusion, supplementation with 0.75% benzoic acid has a positive effect on piglets by reducing diarrhoea, improving intestinal health and promoting the performance from weaning to finishing. Thus, benzoic acid can be considered a potential alternative that can replace growth-promoting antibiotics.
