Study On The Feeding Effect Of Fermented Pineapple Residue On Beef Cattle In The Late Fattening Period

With the rapid growth of Chinese economy,the demand for high-quality livestock and poultry products,has rapidly increased.Especially in South China,beef consumption has ranked the forefront of the country.However,the shortage of high-quality green roughage has always been an important factor restricting the scale and industrialization of the beef cattle industry in South China.The by-products of fruit processing,such as pineapple residue,have a high feeding value for ruminants after fermentation due to its highyield,wide-source and nutrient-rich,as well as rich in active substances such as flavonoids and plant polyphenols.Therefore,it can be used for the development of new roughage resources.The objectives of this study are to explore the possibility of fermented pineapple residue as a new type of fermented feed for beef cattle,accordingly to broaden the choice of ruminant diets in South China,and investigate whether it has the potential as a functional feed.A total of 30 Simmental fattening cattle(age around 20 months,weigh 546±44 kg),were selected and then divided into three test groups based on the equalization of completely randomized design in this experiment.The experimental treatment was three levels of fermented pineapple residue: 0,25 and 50%,as an additive amount in roughage dry matter(CON,T25 and T50,respectively).The whole trial has 3 d of adaptation period and 30 d of feeding period.During the trial period,of growth indexes,heat stress indexes,blood indexes,rumen fermentation parameters,and microflora composition were collected.And at the end of the trial,beef meat quality and nutrition indexes were detected after slaughtering.The results are as follows:1)The average daily gain(ADG)increased with the augment in the proportion of fermented pineapple residue in the diet(P>0.05),and the average dry matter intake(DMI)/ADG also decreased significantly(P<0.01);the daily gross profit per head of the 25%and 50% fermented pineapple residue added group was RMB 5.34 and RMB 3.69 more than that of control group,respectively.2)The fermented pineapple residue added groups significantly reduced the rectal temperature of fattening cattle(Contrast P<0.01).Besides,the contents of serum oxidative stress indicators HSP70,BHBA and MDA were significantly decreased in B50 group compared with CON group(P<0.05),together with that SOD,GSH-Px and OH-enzyme activities were significantly increased(P<0.05).3)Compared with the control group,the T4 and TC contents in the serum of the 50%added group were most significantly higher(P<0.01),the T3 content was significantly higher(P<0.05),and the CR content was significantly reduced(P< 0.01).The serum ALB content in the T25 group increased significantly(P<0.05),and the CR content decreased significantly(P<0.05)compared with the control group.4)As for the immune indexes,IFN-γ,CRP,IgA,IgG and IgM contents of the treatment groups increased with the augment of the amount of fermented pineapple residue,while IL-6 showed a downward trend.Compared with the control group,the IFN-γ and IgM indexes in the T50 group were significantly increased(P<0.05),and the CRP index was most significantly increased(P<0.01);the CRP content in the T25 group was significantly increased(P<0.01);IL-4 indicators were observed very significant changes in both treatment groups.5)The fat content of fattening cattle muscle in T50 group increased significantly(P<0.05).The content of tyrosine,proline and phenylalanine in T25 group was significantly higher than that in CON group(P<0.05);the content of cysteine in T50 group was 0.18 g /100 g more than that in CON group(P<0.05),while The content of proline was significantly increased by 6.21% compared with the CON group(P<0.01).Moreover,the essential amino acid compositions of the beef rating meeting the high-quality standard of FAO/WHO model of T50 group were 2 more than the 25% added group and 3 more than the CON group.6)The ruminal pH in the T50 group was significantly higher than that in the CON group,while the content of isobutyric acid and isovaleric acid was significantly reduced(P<0.05).The pineapple residue did not affect the rest of the fermentation parameters.7)The results of β diversity analysis showed that there were significant differences in the bacterial flora of rumen fluid between the treatment groups(P<0.05).At phylum levels,the relative abundance of Spirochaetes in the T25 group was significantly lower than that of the control group and the T25 group(P<0.05).At species levels,the relative abundance of Lachnospiraceae＿bacterium＿RM44 in the T50 group were significantly higher than it in the control group(P<0.05).In summary,the addition of fermented pineapple residue to the daily diet can improve the growth performance and economic benefits of fattening beef cattle,and it is feasible to use it in the later stage of fattening beef cattle.Meanwhile,with the increase of the proportion of pineapple residue,it can significantly alleviate the heat stress of fattening beef cattle,and improve the amino acid composition and fat content of muscles.Thus,fermented pineapple residue can be considered as functional feed.