Research On The Change Law Of Short-chain Ketonic Acid Content In The Carrier And Feedstuff With The Time Of Storage

Organic acid that is a new non-residue feed additive. It can improve animal growth and development by regulating the metabolism in vivo. It can promote the growth of livestock, enhance immunity of the organism, improve feed conversion rate. But the report on the test of organic acid is relatively few. And there is less any study on the change law of organic acid in the carrier and feedstuff with the time of storage. Our Research Team has exploited a new kind of organic acid feed additive that was short-chain ketonic acid. On the basis of the previous research, the experiment provided a method of organic acid which was aimed at establishing a stable, accurate and rapid method for detecting the content of organic acid. Using this method in the determination of organic acid content in the carrier and feedstuff with the extension of storage time, so as to select suitable organic carrier materials. At the same time, whether the organic acid content was influenced by granulation process and different packaging forms was studied, and to observe the change law of organic acid with the time of storage. This study includes the following aspects:(1) The study on the detection method of organic acid by HPLC(high performance liquid chromatography): The method for determination of short-chain ketonic acid in the feedstuff was developed by high performance liquid chromatography(HPLC). Dikma Technologies- C18 column was used with methanol: 0.01mol/L KH2PO4-buffer solution p H2.0(8:92, V/V) as the mobile phase at a flow rate of 0.8m L·min-1, and detection wavelength was 268 nm, quantified by external standard method. The results showed that: Short-chain ketonic acid had good linear in the range of 0.50~20.00mg/m L(0.9999), and the recovery rate was 97.33%. The method is simple, sensitive and reproducible and suitable for the determination of short-chain ketonic acid in the feedstuff.(2) Effects of different carrier on the content of organic acid: Mix short-chain ketonic acid respectively in four kinds of carrier(Ⅰ= rice bran, Ⅱ= soybean meal2: rice bran1, Ⅲ = rice husk, Ⅳ= soybean meal2: rice husk1). The content of organic acid was 20%, and the storage life was 150 d. The change law of organic acid in the different carrier with the time of storage was investigated, aim to select suitable organic carrier materials. The results showed that, with the increase of the storage time, the content of organic acid in the carrier declined. Within 70 storage life, the content of organic acid tended to be linear form slowly down. 70~150 d, organic acid content in every experimental group still continues to decline, but did not show significant changes, tended to be stable. At 150 d, the reduction rate of organic acid content in four kinds of carriers were 8.87%(P<0.01), 6.92%(P<0.01), 9.45%(P<0.01), 7.91%(P<0.01)respectively. Among them, the retention rate of test group Ⅱ(soybean meal2: rice bran1) was the highest, the test group Ⅳ(soybean meal2: rice husk1) was the second.(3) Effects of the storage time on the content of organic acid in the feedstuff: Short-chain ketonic acid was added to the feedstuff in the form of four carriers( Ⅰ= rice bran, Ⅱ= soybean meal2: rice bran1, Ⅲ = rice husk, Ⅳ= soybean meal2: rice husk1). The content of organic acid was 1.2%, and the storage time was 70 d. The change law of organic acid in the feedstuff of different carriers over the time of storage was investigated. The results showed that, the time of storage and the content of organic acid were significantly negative correlated. Overall, orga nic acid content declined gently within 30 d, organic acid content reduced rapidly among 30~50 d, the change of organic acid content was trend to stable among 50~70 d. At 70 d, the reduction rate of organic acid content in the every experimental group(Ⅰ, Ⅱ, Ⅲ, Ⅳ) were 11.97%(P<0.01) 、5.64%(P<0.01)、10.66%(P<0.01)、11.01%(P<0.01) respectively. Among them, the retention rate of test group Ⅱ(soybean meal2: rice bran1) was the highest.(4) Effects of the storage time on the content of organic acid in the powder and grain feedstuff: This experiment was conducted to investigate the effects of granulation process on organic acid in the powder and the effects of different packaging forms(Ⅰ= woven bag, Ⅱ= lined with polyethylene film bag, Ⅲ = hermetic bag) on the change law of organic acid with the time of storage. The content of organic acid in the feedstuff was 1.2%,and the storage time was 70 d. The results showed that,(1) During the process of the feed granulation, the loss rate of organic acid content was 0.78%. The stability of organic acid was satisfactory.(2) With the increase of the storage time, the content of organic acid in the powder was significantly declined. The reduction rate of organic acid content under three storage methods were 17.37%, 12.99%, and 12.83%(P<0.01) respectively.(3) The reduction rate of three groups were 5.36%, 5.05%, and 3.94%(P>0.05) respectively. The test showed there were not significant differences in the every group, and the content of organic acid in the grain feedstuff decreased less than the one in the powder with the increase of the storage time.In summary, the method for determination of short-chain ketonic acid content in the feedstuff was developed by HPLC. And this method measured the content of short-chain ketonic acid to select suitable organic carrier material, it was(soybean me al2: rice bran1). With the increase of the storage time, the content of short-chain ketonic acid in the carrier and feedstuff declined. The content of short-chain ketonic acid displayed decrease trend at first, and then decreased slowly with prolongation of the storage time, the change of short-chain ketonic acid content was trend to stable. At the same time, short-chain ketonic acid was stable; granulation process has no influence on short-chain ketonic acid. The preserving rate of organic acid in the grain feedstuff was greater than the one in the powder. Sealed packaging methods were positive for the storage of short-chain ketonic acid. Furthermore, short-chain ketonic acid was volatile in the feedstuff.