Chestnut tannin extract modulates growth performance and fatty acid composition in finishing Tan lambs by regulating blood antioxidant capacity, rumen fermentation, and biohydrogenation

Abstract

Tannins as plant extracts have emerged as promising and potential alternatives for antibiotics in modern livestock cultivation systems. This study investigates the effect of dietary chestnut tannin extract (CTE) in finishing Tan lambs. Twenty-seven male Tan lambs were randomly divided into three groups: (1) control group (CON; basal diet); (2) low-dose CTE group (LCTE; basal diet + 2 g/kg CTE, dry matter [DM] basis); (3) high-dose CTE group (HCTE; basal diet + 4 g/kg CTE, DM basis). The HCTE group exhibited markedly higher average daily gain (ADG) and DM intake than CON (P < 0.01). The ruminal total volatile fatty acid concentration increased linearly with increasing CTE supplementation (P < 0.01), while the opposite trend was observed for butyrate molar proportion (P < 0.01). Upon increasing CTE dosage, plasma glucose, high-density lipoprotein cholesterol, glutathione peroxidase, and superoxide dismutase content increased linearly (P < 0.05), whereas low-density lipoprotein cholesterol and urea nitrogen decreased linearly or quadratically (P < 0.05), respectively. A linear increase was also observed in ruminal t6 C18:1 and t9, c12 C18:2 proportions (P < 0.01), and plasma C18:2n-6 and n-6 polyunsaturated fatty acids proportions with increased CTE supplementation (P < 0.01). In the longissimus dorsi muscle, the atherogenic index decreased linearly (P < 0.05), while c11 C18:1 and C20:5n-3 increased linearly (P < 0.05). Moreover, c9, t11 conjugated linoleic acids proportion increased in subcutaneous fat with CTE supplementation (P < 0.01). In conclusion, Dietary CTE enhances the ADG of finishing Tan lambs in a dose-dependent manner, modulates plasma metabolites and antioxidant capacity, and improves rumen fermentation and body fatty acid composition. These results provide a reference for the rational application of CTE in ruminant production.

Keywords: Chestnut tannin extract; Fatty acids; Growth performance; Plasma metabolites; Rumen fermentation.

Fig. 1

Effect of different chestnut tannin extract doses on growth performance of finishing Tan lambs. (A) initial BW = initial body weight; (B) final BW = final body weight; (C) ADG = average daily gain; (D) DMI = dry matter intake; (E) FCR = feed conversion ratio. CON = control; LCTE = 2 g/kg chestnut tannin extract; HCTE = 4 g/kg chestnut tannin extract. The effects included group (G) effects, linear (L) effects, and quadratic (Q) effects. ^{a, b, c} Values with distinct letters differ significantly (P < 0.05). The error bar represents the standard error of the mean

Fig. 2

Effect of chestnut tannin extract supplementation after 0, 30, or 60 d on the ruminal fermentation characteristics of finishing Tan lambs. (A) pH; (B) NH₃-N; (C) TVFA = total volatile fatty acids; (D) butyrate; (E) acetate; (F) valerate; (G) isovalerate; (H) isobutyrate; (I) propionate; (J) BCVFA = branched-chain volatile fatty acids; (K) acetate/propionate. CON = control; LCTE = 2 g/kg chestnut tannin extract; HCTE = 4 g/kg chestnut tannin extract. The effects included group (G) effects, time (T) effects, and interaction effects between group and time (G × T), as well as linear (L) and quadratic (Q) effects. The mean and standard error of the mean are plotted. Bars with distinct superscripts (a–c) differ significantly (P < 0.05)

Fig. 3

Plasma biochemical indices in finishing Tan lambs fed chestnut tannin extract within three sampling days. (A) HDL-C = high-density lipoprotein cholesterol; (B) GLU = glucose; (C) BUN = urea nitrogen; (D) LDL-C = low-density lipoprotein cholesterol; (E) TG = triglycerides; (F) CHOL = cholesterol; (G) TP = total protein; (H) ALB = albumin; (I) GLB = globulin; (J) ALB/GLB = albumin/globulin. CON = control; LCTE = 2 g/kg chestnut tannin extract; HCTE = 4 g/kg chestnut tannin extract. The effects included group (G) effects, time (T) effects, and the interaction effects between group and time (G × T), as well as linear (L) and quadratic (Q) effects. Values are mean ± standard error of the mean. Bars with distinct superscripts (a, b) differ significantly (P < 0.05)

Fig. 4

Plasma antioxidant capacity of finishing Tan lambs fed chestnut tannin extract within the three sampling days. (A) GSH-Px = glutathione peroxidase; (B) SOD = superoxide dismutase; (C) T-AOC = total antioxidant capacity; (D) MDA = malonaldehyde. CON = control; LCTE = 2 g/kg chestnut tannin extract; HCTE = 4 g/kg chestnut tannin extract. The effects included group (G) effects, time (T) effects, and the interaction effects between group and time (G × T), as well as linear (L) and quadratic (Q) effects. Values are mean ± standard error of the mean. Bars with distinct superscripts (a, b) differ significantly (P < 0.05)

Fig. 5

Plasma immune function in finishing Tan lambs fed chestnut tannin extract within the three sampling days. (A) IgA = immunoglobulin A; (B) IgM = immunoglobulin M; (C) IgG = immunoglobulin G. CON = control; LCTE = 2 g/kg chestnut tannin extract; HCTE = 4 g/kg chestnut tannin extract. The effects included group (G) effects, time (T) effects, and the interaction effects between group and time (G × T), as well as linear (L) and quadratic (Q) effects. Values are the mean ± standard error of the mean. Bars with distinct superscripts (a, b) differ significantly (P < 0.05)