Mechanisms Of Dietary Supplementation With Acanthopanax Senticosus Extract In Inhibiting Weanling Stress And Promoting Growth Performance In Weaned Piglets

To stduy mechanisms of dietary supplementation with acanthopanax senticosus extract (ASE) in inhibiting weanling stress and promoting growth performance in weaned piglets, 96 Duroc×Landrace×Yorkshire pigs weaned at 21 d of age with an average initial body weight (BW) of 5.6 kg were selectecd. The piglets were randomly assigned into 3 treatments, with 4 duplicates each by weight and sex to investigate the growth performance, diarrhea, serum biochemical parameters and levels of serum hormone, immunity indexs, intestinal microbial community and intestinal morphology. Another 6 pigs were selected to investigate the apparent digestibility of nutrients with 2×3×3 Latin square design. The pigs were fed basal diet adding with 0, 0.1% ASE and 0.07% antibiotics, respectively. The results showed as following:1) Dietary supplementation of ASE improved growth performance and reduced diarrhea of early-weaned piglets, and the effects were identified with antibiotics. During the three weeks, average daily gain (ADG) of ASE group and antibiotics group were increased significantly compared with control group, and feed/gain (F/G) significantly decreased (P<0.01). ADG in ASE group increased by 12.9% (P<0.05), while F/G decreased by 18.4% (P<0.01) at the end of feeding trial. There were no differences in growth performance between the ASE and antibiotics group. Dietary supplementation of ASE and antibiotic decreased (P<0.05) the diarrhea frequency by 55.6% and 52.2%, respectively, compared with control group.2) Dietary supplementation of ASE improved apparent digestibility of totle Energy, phosphorus (P) and calcium (Ca). The apparent digestibility of Ca of ASE group was higher than antibiotics and control (P<0.05), the apparent digestibility of phosphorus of ASE were higher than the other two groups too, but the difference were not significant (P>0.05).3) Dietary supplementation with ASE increased the serum contents of low-density lipoprotein (LDL), cholesterol (CHO), glucose (GLU), free triiodothyronine (FT₃), free thyroxine (FT₄), growth hormone (GH), insulin-like growth factor-1 (IGF-1), increased FT₃/FT₄ and serum activity of alkaline phosphatase (ALP), and decreased contents of Serum urea nitrogen (SUN). The serum contents of LDL, CHO, GLU, FT₃, FT₄, GH and IGF-1 decreased and then increased back. ASE increased contents of LDL, CHO and GLU by 18.5%, 31.6% (P<0.05), 11.4% on day 7 after weaned, and 29.9% (P<0.05), 12.1%, 12.0% on day 14, respectively. The contents of SUN increased after weaned, ASE group and antibiotics were lower than that of control group. Serum activity of ALP had a tendency of upgrade with change of ADG The serum contents of FT3, IGF-1 and value of FT₃/FT₄ of ASE group were signifiantly higher than control group.There were no difference between ASE and antibiotics group (P<0.05).4) The serum content of cortisol (Cor), adrenocorticotrop(h)ic hormone (ACTH) and corticotropin releasing hormone (CRH) increased and then decreased back after weaned. Dietary supplementation with ASE could decrease the contents of Cor and ACTH, maintenance the content of CRH in a normal range, in another word ASE could inhibit accentuation of hypothalamic-pituitary-adrenocortical (HPA) axis function. The serum content of interleukin-2 (IL-2) and immunoglobin G (IgG) decreased during day 0 and day 14 after weaned. Dietary supplementation with ASE and antibiotics could significantly increased the serum content of IL-2 on day 7 and 14 (P<0.05). On day 14 ASE group still had a higher level of IgG than control diet (P<0.05).5) After the weaning process, pigs have a decreased invillus height and increased crypt depth, supplemental ASE increased the villus height of Duodenum, Jejunum and ileum by 14.8%, 13.7%, 10.0% (P<0.01), decreased crypt depth by 17.9%, 9.1%, 12.1% (P<0.01), respectively. Compared with antibiotic, supplementation with ASE had higher villus height (P<0.05) at Duodenum and Jejunum, lower crypt depth (P<0.05) at Jejunum and Ileum.6) Denaturing gradient gel electrophoresis (DGGE) results indicated that density of pathogenic bacteria increased after weaned, favorable bacteria decreased, and Supplemental ASE and antibiotic had a effective effect on keeping up density of favorable bacteria or reducing pathogenic bacteria.Similarity indices showed much difference between pre- and pro-weaned, of which ASE had a higher Similarity indices compared with other two groups. It's suggested that microbial flora changed much after weaned, Supplemental ASE and antibiotic could improve disorder of microbial flora. Furthermore, ASE had a better effective tendency than antibiotics.In summary, dietary supplementation with ASE could modulate function of HPA axis and level of hormone correlated growth, impove gut health, elevate immune and digest or metabolism function, thereby inhibit weaned stress, decrease diarrhea and finally promote growth performance under weaning process.