Effects of Forsythia Suspense Extract as an Antibiotics Substitute on Growth Performance, Nutrient Digestibility, Serum Antioxidant Capacity, Fecal Escherichia coli Concentration and Intestinal Morphology of Weaned Piglets

Simple Summary

Weaning stress may reduce feed intake, weight gain and health status of piglets. Antibiotics are used to overcome post-weaning disorders. However, the abuse of antibiotics in pig feed has become a worldwide problem. Previous studies show Chinese herbs have been used as a potential non-antibiotic way to enhance anti-inflammatory and anti-microbial functions of piglets. This study aims to evaluate the effect of Forsythia suspense extract (FSE) as an antibiotics substitute on performance, nutrient digestibility, serum antioxidant capacity, fecal Escherichia coli concentration and intestinal morphology of weaned piglets. The results show that dietary FSE supplementation can substitute antibiotics in improving antioxidant capacity, nutrients digestibility and reducing fecal E. coli content, so as to reduce nitrogen output and diarrhea rate, and eventually enhance growth performance in weaned piglets.

Abstract

The aim of this study is to determine the efficiency of Forsythia suspense extract (FSE) as an antibiotics substitute on performance, nutrient digestibility, serum antioxidant capacity, fecal Escherichia coli concentration and intestinal morphology of weaned piglets. A total of 108 Duroc × (Landrace × Yorkshire) weaned piglets (28 days (d) weaned, average body weight of 8.68 ± 1.36 kg) were randomly assigned into three dietary treatments, six pens per treatment, three barrows and three gilts per pen. The treatments contained a corn-soybean meal basal diet (CTR), an antibiotic diet (basal diet + 75 mg/kg chlortetracycline; CTC), and an FSE diet (basal diet + 200 mg/kg FSE; FSE). The experiment included phase 1 (d 1 to 14), phase 2 (d 15 to 28) and phase 3 (d 29 to 35). Compared with CTR, piglets fed FSE show improved (p < 0.05) average daily gain (ADG) and average daily feed intake in phase 2, as well as enhanced (p < 0.05) ADG from day 15 to 35 and day 1 to 28. Piglets supplemented with CTC and FSE showed a reduced (p < 0.05) diarrhea rate in phase 1, while piglets fed FSE showed enhanced (p < 0.05) apparent total tract digestibility (ATTD) of dry matter, organic matter, crude protein and gross energy, as well as lower (p < 0.05) nitrogen output in phase 2 compared with CTR and CTC. The content in the form of Colony-Forming Units (CFUs) of fecal E. coli on day 14 and 28 was lower (p < 0.05) in piglets fed FSE in comparison with CTR. The contents of total antioxidant capacity, superoxide dismutase and catalase in serum are enhanced (p < 0.05) compared with CTR and CTC, whereas the concentration of malondialdehyde in serum was decreased (p < 0.05) for piglets fed FSE on day 28 compared with CTC. The villus height to crypt depth ratio in ileum was numerically higher (p < 0.05) in piglets fed FSE in comparison with CTR. In conclusion, dietary FSE supplementation could substitute CTC in improving antioxidant capacity, nutrients digestibility and reducing fecal E. coli content, so as to reduce nitrogen output and diarrhea rate, and eventually improve performance in weaned piglets.

Dietary values of Forsythia suspensa extract in Penaeus monodon under normal rearing and Vibrio parahaemolyticus 3HP (VP3HP) challenge conditions: Effect on growth, intestinal barrier function, immune response and immune related gene expression

Two trials were conducted to determine the effects of dietary Forsythia suspensa extract (FSE) on shrimp, Penaeus monodon, first on growth performance, second on the immune response and immune related gene expression of shrimp. In trial 1, shrimp (mean initial wet weight about 3.02 g) were fed with five diets containing 0% (basal diet), 0.01%, 0.02%, 0.04% and 0.06% FSE in triplicate for 60 days. Growth performance (final body wet weight, FBW; weight gain, WG; biomass gain, BG) of shrimp fed FSE diets were higher (P < 0.05) than that of shrimp fed the basal diet. The survival among all the diets treatments were above 90% and no significant difference was revealed among them (P > 0.05). The antioxidant capacity (total antioxidant status, TAS; glutathione peroxidase, GSH-Px) appears in the trend of firstly increasing then decreasing with the increasing of dietary FSE levels. The highest value of TAS and GSH-Px were found in shrimp fed 0.02% FSE diet and were significantly higher than that of shrimp fed the basal and 0.06% FSE diets (P < 0.05). Hepatopancreas malondialdehyde (MDA) of shrimp fed FSE diets were lower (P < 0.05) than that of shrimp fed the basal diet. Total haemocyte count of shrimp fed the basal diet was lower (P < 0.05) than that of shrimp fed FSE diets. Haemolymph clotting time of shrimp had the opposite trend with the total haemocyte count of shrimp. No significant differences were found in haemolymph biomarkers of intestinal permeability (endotoxin and diamine oxidase) and in molecular gene expression profiles of heat shock protein 70 (Hsp 70) mRNA and hypoxia inducible factor-1α (HIF-1α) mRNA in haemolymph of shrimp among all diet treatments (P > 0.05). In trial 2, a pathogenic strain of Vibrio parahaemolyticus 3HP (VP_3HP) injection challenge test was conducted for 6-day after the rearing trial and shrimp survival were also compared among treatments. Survival of shrimp fed diets supplemented with 0.01%-0.02% FSE were higher than that of shrimp fed the basal and 0.06% FSE diets (P < 0.05). Dietary FSE supplementation produced stronger hepatopancreas antioxidant capacity (TAS, GSH-Px) (P < 0.05) and higher glutathione (GSH) level (P < 0.05), lower superoxide dismutase activity (SOD) (P < 0.05), higher total haemocyte count (P < 0.05), lower haemolymph clotting time (P < 0.05), lower MDA and carbonyl protein concentration (P < 0.05), lower haemolymph biomarkers of intestinal permeability (endotoxin and diamine oxidase) (P < 0.05), generated lower molecular gene expression profiles of HSP 70 mRNA and higher HIF-1α mRNA (P < 0.05) than the basal diet. The immune response were characterized by lower TAS and higher antioxidant enzyme activities (SOD, GSH-Px) and higher oxidative stress level (MDA and carbonyl protein) and higher haemolymph biomarkers of intestinal permeability (endotoxin and diamine oxidase) compared to levels found in trail 1. However, the total haemocyte counts and haemolymph clotting times were not changed in 0.01%-0.02% FSE diets treatments between trial 1 and trial 2 (P > 0.05). The molecular gene expression profile of Hsp 70 mRNA was increased while HIF-1α mRNA was decreased when compared to trial 1. In conclusion, results suggested that dietary intake containing FSE could enhance the growth performance and antioxidant capacity of P. monodon and furthermore reduce oxidative stress and immune depression challenged by a pathogenic strain of Vibrio parahaemolyticus stress. Considering the effect of FSE on both growth performance and immune response of P. monodon, the level of FSE supplemented in the diet should be between 0.01% and 0.02%.