Effect of colistin and tylosin used as feed additives on the performance, diarrhea incidence, and immune response of nursery pigs

Abstract

For the last several decades, antimicrobial compounds have been used as feed additives to promote piglet growth at weaning, through the prevention of subclinical and clinical disease. However, few studies have assessed the influence of these antibiotics on the immune response of nursery pigs, as well as the relation between performance, health, and immunity of animals that receive feed additives. Therefore, the present study aimed to evaluate the effects of colistin and tylosin when used as feed additives on the performance, incidence of diarrhea, and immune response of nursery pigs. In this study, 72 weaned pigs (average age, 28 days) were allotted into one of three treatment groups: a control group (feed with no antibiotics), tylosin group (feed containing 22 ppm tylosin), and colistin group (feed containing 20 ppm colistin). Weekly, during a five week period, the average daily feed intake, average daily gain, and feed conversion ratio of the pigs were evaluated. Stools were scored daily, in accordance with a fecal texture scale. Blood samples were collected on the day of housing (d0) and on d7, d21, d28, and d35 for immune cell phenotyping. The results of this study showed that piglets in both the colistin and tylosin groups exhibited a significantly higher average daily feed intake, resulting in a higher body weight at the end of the experimental period (d35) when compared with piglets from the control group. Colistin and tylosin also significantly reduced the incidence of diarrhea. Colistin and tylosin modulated the piglets' immune responses, particularly on d28, by changing the percentage of circulating B lymphocytes, CD4 + CD8 + T cells, and the CD4:CD8 ratio. ResumoNas últimas décadas, os compostos antimicrobianos têm sido utilizados como aditivos alimentares para promover o crescimento de leitões ao desmame, por meio da prevenção de doenças clínicas e subclínicas. No entanto, poucos estudos avaliaram a influência destes antibióticos sobre a resposta imune de leitões na fase de creche, bem como a relação entre o desempenho, a saúde e a imunidade dos animais com o uso destes aditivos. Sendo assim, o presente estudo teve como objetivo avaliar o efeito da colistina e da tilosina como aditivos na alimentação sobre o desempenho, incidência de diarreia e resposta imune de leitões na fase de creche. Para isso, foram utilizados 72 suínos recém-desmamados, com 28 dias de idade em media, divididos em três tratamentos: grupo controle (ração sem antibiótico), grupo tilosina (ração com 22 ppm de tilosina), grupo colistina (ração com 20 ppm de colistina). Semanalmente, durante cinco semanas, foi analisado o consumo deração diário, o ganho de peso diário e a conversão alimentar dos leitões. As fezes foram avaliadas diariamente, com a atribuição de escores relacionados à sua consistência. Amostras de sangue foram coletadas no momento do alojamento (d0) e aos d7, d21, d28 e d35, sendo submetidas à técnica de citometria de fluxo. Os resultados demonstraram que tanto o grupo colistina como o grupo tilosina promove...

Maximum levels of cross‐contamination for 24 antimicrobial active substances in non‐target feed. Part 9: Polymyxins: colistin

“…In weaned piglets, most of the studies (12) showed that dietary colistin supplementation at 12 to 200 mg/kg feed had positive growth-promoting effects in piglets (Guerra et al (2007), 12 mg colistin sulfate/kg feed; Mazutti et al (2016), 20 mg colistin/kg feed; Yang et al (2012) and Yu et al (2017), 20 mg colistin sulfate/kg feed; Cui et al ( 2019), 40 mg colistin sulfate/kg feed; Sbardella et al (2016) and Silva-J unior et al (2020), 40 mg colistin/kg feed; Wan et al (2015), 60 mg colistin sulfate/kg feed; Cao et al (2019), 100 mg colistin sulfate/kg feed; Kong et al (2007), Liu et al (2016) and Yin et al (2009), 200 mg colistin/kg feed). Only in two studies no growth-promoting effects of colistin in piglets were observed when administered in the diet (Santana et al (2015), 40 mg colistin sulfate/kg feed; Conde et al (2001), 150 mg colistin/kg feed).…”

“…In the study of Mazutti et al. ( 2016 ), a total of 72 weaned piglets (unspecified breed/genotype; 28 days of age) were distributed in 24 pens in groups of three animals and allocated to three dietary treatments. Two basal diets (pre‐starter and starter phase) were either not supplemented or supplemented with different treatments.…”

Maximum levels of cross‐contamination for 24 antimicrobial active substances in non‐target feed. Part 6: Macrolides: tilmicosin, tylosin and tylvalosin

“…In the study of Mazutti et al. ( 2016 ), a total of 72 weaned piglets (unspecified breed/genotype) at 28 days of age were allocated to three dietary treatments and distributed in eight pens per treatment, in groups of three animals. Two were the relevant treatments obtained from two basal diets – pre‐starter and starter – which were either not supplemented (control) or supplemented with tylosin (unspecified form) at the concentration of 22 mg/kg feed.…”

“…In five studies in weaned piglets, dietary tylosin supplementation at 22–1,000 mg/kg feed had growth‐promoting/increase yield effects in piglets (Mazutti et al. ( 2016 ), 22 mg tylosin/kg feed; Livingstone and Livingston ( 1968 ), 40 mg tylosin/kg feed; Yan et al. ( 2011 ), 44 mg tylosin/kg feed; Zhang et al.…”

Understanding of Colistin Usage in Food Animals and Available Detection Techniques: A Review

“…For decades, colistin has been used as an additive in livestock feed for promoting growth and treating intestinal infections [ 14 , 15 ] as shown in Figure 2 .…”