| Firstly, this paper was conducted to investigate the appropriate sample weight and the variation of the method for determining non-starch polysaccharides(NSP) of feedstuffs by gas chromatography with aiditol acetates derivatives. Then the content of NSP in wheat, wheat bran and middlings ingredients was determined using this method and the correlation between the NSP content and the content of proximate nutrients were also analyzed. Finally, the effect of dietary fiber type on the carbohydrate polysaccharide components and energy digestibility of diets by pigs was determined in the present study. This will provide the reference for the improvement of feed NSP components database and indicating the digestive process of dietary NSP and the effect of NSP on the digestibility of energy.The objective of the first part was to investigate the appropriate sample weight and the variation of the method for determining NSP of feedstuffs by gas chromatography with aiditol acetates derivatives. Firstly, a single factorial completely randomized design with 7 sample weight treatments(0.10, 0.15, 0.20, 0.25, 0.30, 0.40, and 0.50 g) for reference dietary fiber(RDF) was adapted and each treatment contained 3 replicates. The content of NSP in RDF was determined. Then, the variation coefficients for determining NSP of RDF based on the appropriate sample weight was analyzed in 2 batches with 3 replicates per batch. Lastly, the NSP of nine feedstuffs(eg. corn et al.) was repeatedly determined to verify the variation of this method.The results showed as follows: 1) Total NSP of RDF with sample weight for 0.10,0.15,0.20, and 0.25 g(P>0.05) were greater than for 0.30,0.40, and 0.50g(P<0.05). 2) The content of monosaccharides, uronic acids, and NSP were not affected by the batch(P>0.05).The intra-batch, inter-batch, and total coefficient of variation(CV) for soluble(S), insoluble(I), and total(T) NSP were less than 11.57%, 3.19%, 3.01%, respectively. 3) The content of SNSP was less than INSP in nine feedstuffs. The primary monosaccharide components of feed ingredients were arabinose, xylose, and glucose. In conclusion, 22-55 mg TNSP(the approximate content of TNSP in 0.10 g and 0.25 g RDF) of sample weight was appropriate and the CV for TNSP were less than 3.01% in the present method using gas chromatography with aiditol acetates derivatives.The objective of the second part was to determine the content of NSP, starch and proximate nutrients in wheat, wheat bran and wheat middlings ingredients and analyze the correlation between the content of NSP and proximate nutrients. The results showed as follows:1) Starch was the most primary component in wheat and wheat middlings, whereas the NSP content was the greatest in wheat bran; the content of crude protein, ether extract and crude ash for wheat bran were greater than for wheat and wheat middlings; the INSP content was higher than the SNSP content for all ingredients, arabinoxylans(AX) was the most primary component of the NSP, and cellulose took second place.2) The range of the CV of the nutrient content in different wheat, wheat barn and wheat middilings varieties were 4.31%-32.04%,5.59%-21.89%,4.00%-25.91%, respectively. The variation of the content of soluble AX(SAX) were the highest in all nutrients. The starch content was negatively correlated with the NSP content, whereas there was a positive relationship between the content of NSP components and TNSP content, the content of cellulose and AX content, respectively. But there was only a significantly positive relatation between the content of crude ash and NSP components content in wheat middlings. The AX content was higher, the branching degree in AX was lower.The objective of the third part was to determine the effect of dietary fiber type on the digestibility of carbohydrate polysaccharide components and energy. Six ileal-cannulated pigs were allotted to 3 treatments in a replicated 3 × 3 Latin square. Three treatments were consisted of control group(corn and soybean meal), inulin(INU) group(corn and soybean was partly replaced by 5% inulin) and carboxymethylcellulose sodium(CMC) group(corn and soybean was partly replaced by 5% CMC).The apparent ileal digestibility(AID) and apparent total tract digestibility(ATTD) of dietary carbohydrate polysaccharide components and energy, and the concentration of volatile fatty acids(VFA) in the feces and ileal digesta were determined. The results showed that: 1)The AID of gross energy(GE) and carbohydrate polysaccharide components(except cellulose and β-glucan) in the INU group were less than in the control and CMC groups(P<0.05). The AID of β-glucan in the CMC diet was greater than in the other diets(P=0.01). 2)The ATTD of total CHO, NSP components(except insoluble AX, SAX and β-glucan) and GE, and the fecal VFA concentration in the CMC diet were less than in the other diets(P<0.05). 3) The hindgut fermentation(HF) of TNSP, INSP and GE were greater(P<0.05) for pigs fed the INU diet than for pigs fed the other diets. The HF of SNSP, β-glucan and cellulose in the CMC group were less than in the other groups(P<0.05). 4) There was strong linear relationship between the ATTD of carbohydrate components and the ATTD of energy(P<0.01). The linear relationship between the HF of carbohydrate components and the HF of energy was also strong(P<0.01).5) The HF of NSP components were significantly correlated with the VFA concentration in the fecal samples(P<0.05).In conclusion, addition of 5% inulin into a diet reduced the digestibility of dietary nutrients in the upper gut and increased hindgut fermentation. Inclusion of 5% CMC into a diet had low hindgut fermentation and the ATTD of dietary nutrients was also low. The different NSP components would produce different type of VFA after hindgut fermentation. The dietary fiber type has affected the digestion and utilization of nutrients and energy by altering the digestive site and the degradation of dietary nutrients. |
PDF Full Text Request