Effects of Epidermal Growth Factor and Insulin-like Growth Factor-Ⅰ on Immune Function in Weaned Piglets

Article Sharing | Effects of Epidermal Growth Factor and Insulin-like Growth Factor-Ⅰ on Immune Function in Weaned Piglets

Source: Li Yao, Shan Anshan, Chan Long, Lü Peng. Effects of Epidermal Growth Factor and Insulin-like Growth Factor-Ⅰ on Immune Function in Weaned Piglets[J]. Chinese Journal of Animal Science, 2006, 42(3): 17-19

Link:  表皮生长因子和胰岛素样生长因子-I对21日龄断奶仔猪内分泌功能的影响 - 中国知网

Abstract

A total of 37 weaned Landrace piglets at 21 days of age were randomly divided into four groups: epidermal growth factor (EGF), insulin-like growth factor-Ⅰ (IGF-Ⅰ), basal diet, and natural suckling, with three replicates per group and three piglets per replicate. The dosage of EGF and IGF-Ⅰ was 17.86 μg/d. The effects of these factors on the immune function of early-weaned piglets were investigated. The results showed that the splenic lymphocyte transformation rate in both the EGF and IGF-Ⅰ groups was significantly higher (P < 0.01) than that in the basal diet group. The content of SIgA in the posterior jejunal mucosa was also significantly higher (P < 0.01) in the EGF and IGF-Ⅰ groups compared to the basal diet group, and the splenic lymphocyte transformation rate in the EGF group was higher than that in the IGF-Ⅰ group. The number of intraepithelial lymphocytes in the mucosa of all segments of the small intestine in the EGF group was significantly higher (P < 0.01) than that in the basal diet group. The number of intraepithelial lymphocytes in the jejunum and ileum mucosa in the IGF-Ⅰ group was significantly higher (P < 0.01) than that in the basal diet group. The number of intraepithelial goblet cells in the ileum mucosa in the EGF group was significantly higher (P < 0.01) than that in the basal diet group, while the number of intraepithelial goblet cells in the ileum mucosa in the IGF-Ⅰ group was significantly lower (P < 0.01) than that in the natural suckling group. Epidermal growth factor and insulin-like growth factor-Ⅰ can enhance the immune function of early-weaned piglets.

Introduction

Early weaning can shorten the reproductive cycle of sows, improve the health and production performance of both sows and growing pigs, and enhance the economic efficiency of sow breeding. Studies have shown that a lack of colostrum in animals can lead to delayed gastrointestinal development, growth retardation, and reduced immunity, thereby affecting production performance and resulting in early postnatal mortality. Breast milk provides essential nutrients for the development of newborn mammals, and peptide growth factors such as epidermal growth factor (EGF) and insulin-like growth factor-Ⅰ (IGF-Ⅰ) play a critical role in the intestinal growth and development, cell proliferation, growth, differentiation, and immune function of newborn animals. Therefore, breast milk is vital for the survival and development of newborn mammals. This experiment investigated the effects of porcine milk-derived EGF and IGF-Ⅰ on the immune function of 21-day-old weaned piglets, aiming to provide a basis for overcoming early weaning syndrome in piglets.

Materials and Methods

Thirty-seven healthy 21-day-old weaned Landrace piglets from three litters were selected. Based on the principles of similar body weight and the same sex, they were randomly divided into four groups, with three replicates per group and three piglets per replicate. The initial body weights showed no significant differences among the groups (P > 0.05), with an average initial body weight of (5.99 ± 0.65) kg. This experiment followed a single-factor design with four treatments and three replicates. The four treatments were EGF, IGF-Ⅰ, basal diet, and natural suckling (EGF: 2.19 μg/L, IGF-Ⅰ: 16.44 μg/L). The basal diet was the same for all treatments. The dosage of both EGF and IGF-Ⅰ was 17.86 μg/d, administered in four equal daily doses. The natural suckling group was allowed normal suckling while being supplemented with the basal diet. The experiment commenced on the weaning day (21 days of age) and lasted for a total of 14 days. The composition and nutritional levels of the experimental diet are shown in Table 1.

Table 1 Formulation and Nutritional Level of the Experimental Basal Diet

Results

Effects of EGF and IGF-Ⅰ on Splenic Lymphocyte Transformation Rate in 21-Day-Old Weaned Piglets

Table 2 Effects of EGF and IGF-I on Splenic Lymphocyte Transformation Rate in 21-Day-Old Weaned Piglets (n=6)

Note: Different lowercase letters in the superscripts within the same column indicate significant differences (P < 0.05). The same applies to the tables below.

As shown in Table 2, the splenic lymphocyte transformation rates in both the EGF group and the IGF-Ⅰ group were significantly higher (P < 0.05) than those in the basal diet group, while showing no significant difference (P > 0.05) compared to the natural suckling group. Furthermore, the splenic lymphocyte transformation rate in the EGF group was higher than that in the IGF-Ⅰ group.

Effects of EGF and IGF-Ⅰ on SIgA Content in Small Intestinal Chyme of 21-Day-Old Weaned Piglets

Table 3 Effects of EGF and IGF-Ⅰ on SIgA Content in Small Intestinal Chyme of 21-Day-Old Weaned Piglets (n=6)

As can be seen from Table 3, the SIgA content in the intestinal mucosa of the distal jejunum was significantly higher (P < 0.01) in both the EGF group and the IGF-Ⅰ group compared to the basal diet group, while no difference was observed when compared to the natural suckling group.

Effects of EGF and IGF-Ⅰ on the Number of Intraepithelial Lymphocytes in the Small Intestine of 21-Day-Old Weaned Piglets

As shown in Table 4, the number of intraepithelial lymphocytes in all segments of the small intestinal mucosa in the EGF group was significantly higher (P < 0.01) than that in the basal diet group and was comparable to the natural suckling group. The number of intraepithelial lymphocytes in the jejunal and ileal mucosa of the IGF-Ⅰ group was also significantly higher (P < 0.01) than that in the basal diet group, though it still showed a certain gap compared to the natural suckling group.

Effects of EGF and IGF-Ⅰ on the Number of Goblet Cells in the Small Intestinal Epithelium of 21-Day-Old Weaned Piglets

Table 5  Effects of EGF and IGF-Ⅰ on the Number of Goblet Cells in the Small Intestinal Epithelium of 21-Day-Old Weaned Piglets (Number of Goblet Cells per 100 Intestinal Epithelial Cells) (n=6)

As shown in Table 5, the number of goblet cells in the ileal mucosa of the EGF group was significantly higher (P < 0.01) than that in the basal diet group and was comparable to the natural suckling group. In contrast, the number of goblet cells in the ileal mucosa of the IGF-Ⅰ group showed no significant difference (P > 0.05) from the basal diet group and was significantly lower (P < 0.01) than that in the natural suckling group.

Discussion and Conclusion

The addition of an appropriate dosage of EGF and IGF-Ⅰ to the diet of early-weaned piglets can significantly enhance their immune function, playing an important role in mitigating early weaning syndrome.