| China is a livestock farming powerhouse,with its pig production accounting for over half of the world’s total output.However,China suffers from severe shortages in feed resources,especially protein feed materials such as soybean,which heavily rely on imports and severely limit the development of the industry.Additionally,in 2020,China issued a "ban on antibiotics" that strictly prohibits the use of growth-promoting antibiotics in animal feed.This "double-edged sword" protects human medicine safety while reducing animal growth performance and disease resistance.China has abundant mulberry leaf resources,which have high nutritional value and are rich in various nutrients,with crude protein content similar to alfalfa or even higher in some varieties.Mulberry leaves also contain multiple bioactive components with high medicinal value.However,except for traditional sericulture that partially utilizes mulberry leaves,most of them remain unused,which results in serious waste of resources.Therefore,making good use of mulberry leaf resources not only helps alleviate the severe shortage of protein feed materials but also replaces the use of antibiotics in feed,promotes animal growth,and improves their disease resistance.This study conducted a silage fermentation experiment on mulberry leaves.Mulberry leaves were mixed with corn flour in three ratios: 80:20,90:10,and 100:0,which were divided into three major groups.Probiotic additives were added to each major group,including the Lactobacillus plantarum + Bifidobacterium bifidum +SN-6 group,Real+ B+ SN-6 group,and the group without probiotics.There were nine small groups in total,numbered I to IX.Firstly,small packages of silage fermentation were made to select the most suitable plan for making silage fermented mulberry leaves,and then this plan was scaled up for further experimentation.The enlarged fermentation products were then fed to weaned piglets for feeding trials.The trial pigs were divided into three groups,control group,2.5% group,5%group,with three repeats per group and 36 pigs per group.The control group was fed with regular basal feed,while the experimental groups were fed with feed containing 2.5% or 5.0%fermented mulberry leaves.After 28 days of feeding,the growth performance,antioxidant indicators,and immune indicators were tested.The results of the experiment are as follows:1.Sensory evaluation: After 25 days of mulberry leaf small bale ensiling fermentation,it was found that groups I,II,IV and V,in which both cornmeal and probiotics were added,had the highest rating of 1 as evaluated by the German Agricultural Association(DLG).These samples had a sour and fragrant aroma,loose texture,and yellow-green color.Groups III,VI,VII and VIII,which only added cornmeal or probiotics,with pungent smell,received a slightly lower rating of 2 from DLG’s evaluation system.Group IX,which did not add either cornmeal or probiotics,received the lowest rating of 3 from DLG’s evaluation system.When the ratio of mulberry leaves and cornmeal was 80:20 and 100:0,the crude protein(CP)content after fermentation decreased to varying degrees compared to before fermentation.However,when the ratio was 90:10,there was no significant change in CP content before and after fermentation.Four groups were able to degrade acid detergent fiber(ADF),namely groups II,V,VII,and IX,with a respective decrease in ADF content by 1.03%,0.53%,1.63%,and 2.1%(p<0.001)compared to before fermentation.After fermentation,the p H values of groups I to VIII ranged from 4.31 to 4.39,while group IX had the highest p H value at 4.54.Based on the content and composition of various organic acids,Flieg’s scoring method was used to evaluate the quality of fermented mulberry leaves,with all groups receiving a rating of "good".In addition,tests for three toxins were conducted on the fermented mulberry leaves in each group,including aflatoxin B1(AFB1),vomitoxin(DON),and zearalenone(ZEN).Only group VII exceeded the AFB1 content limit,while toxin levels in all other groups were within national standards.Taking into account the overall production cost,sensory evaluation,preservation of nutritional substances,degradation rate of cellulose,and fermentation quality,it is recommended that the optimal ratio of mulberry leaves to cornmeal is 90:10,with the addition of probiotics such as Real+ B +SN-6 for ensiling fermentation of mulberry leaves.2.The above conditions were made into a magnified experiment.The results showed that there was no sign of spoilage after fermentation,and the fermented mulberry leaves had a strong sour and fragrant aroma with a soft texture.The CP content had no significant difference compared to before fermentation(p>0.05),while ADF and NDF contents both significantly decreased(p<0.001).The p H value also dropped to 4.19,and toxin content met national standards.Overall,the fermentation effect of large bale was better than that of small bale.3.Animal experiments have shown that both adding fermented mulberry leaves had no significant effect on the average daily gain(ADG)and average daily feed intake(ADFI)of piglets in conservation.Fermented mulberry leaves were found to reduce feedto-gain ratio(F/G)in weaned piglets.Adding 2.5% fermented mulberry leaves decreased F/G by 6.41%(p<0.05),and adding 5% fermented mulberry leaves decreased F/G by 7.69%(p<0.01).Fermented mulberry leaves could significantly improve the serum SOD activity in weaned piglets.Compared to the control group,adding 2.5% fermented mulberry leaves increased the serum SOD activity of weaned piglets by 12.82%(p<0.01),adding 5%fermented mulberry leaves increased the SOD activity by 17.43%(p<0.001),and adding5% fermented mulberry leaves showed a trend towards increased GSH-PX activity(p=0.08).Adding 2.5% fermented mulberry leaves had no significant effect on the immunoglobulin content in serum,while adding 5% fermented mulberry leaves significantly increased the levels of Ig A and Ig G(p<0.01).In summary,the addition of fermented mulberry leaves to the diet of weaned piglets can significantly improve their production performance,enhance their antioxidant and immune functions.The better dosage for this effect appears to be 5%. |
PDF Full Text Request