| In this paper,the effects of different varieties,different harvest times,different silage methods and different storage time on the whole plant pH,nutrient composition and mycotoxin content of maize were studied systematically.Harvest period and safe and stable storage methods were used to evaluate the utilization rate of nutrients and energy of whole-plant corn by digestion and metabolism test.Nutrition and four mycotoxins(aflatoxin B1,fumaroxin(B1+B2),zearalenone and deoxynivalenol)were detected from five links.The changes of nutrient and mycotoxin in whole-plant corn silage were tested.The results showed that after storage for 42 days,all pH values were less than 4.There was no significant change in nutrient composition and energy between harvest period and between inoculation and non-inoculation,and there was no significant difference in nutrient composition and energy between harvest period and inoculation period 0d before silage and42 d after silage(P < 0.05).The contents of CA and CP were significantly changed(P <0.05)and the contents of NFE and GE were significantly changed(P < 0.05)on the basis of dry matter,both before ensilage and 42 days after silage,the four toxins were in accordance with the state regulations.The lowest detection line.The results of nutrient changes of different maize varieties at different harvest stages showed that: from the point of pH change and storage speed,there were differences among different varieties in terms of maturity period > 2 weeks before maturity period > 4 weeks before maturity period,however,there were differences among different varieties.All the pH values could reach the requirement of "Feed material Maize silage quality Standard" at the3 rd day,and the nutrient composition and the total energy were different during the whole-plant silage harvesting process of different varieties four weeks before the maturity period.But there was no difference between before and after silage,and the contents of DM、OM and GE were significantly different on the basis of air drying 2 weeks before the maturing stage.The contents of DM、OM and GE were significantly different on the basis of air drying at 0 week before the period(P < 0.05).The effects of storage methods and silage time on the nutrition and safety stability of whole corn plants showed that the different storage methods of whole-plant corn had no significant effect on pH and mycotoxin content during fermentation,but on the fresh basis.The effect of air drying and dry matter on nutrient content was not significant.The experiment on the utilization of whole-plant nutrient and apparent digestible nutrient yield of maize showed that different proportion of whole corn in diet would affect the utilization rate of crude fiber in growing pigs.With the increase of proportion,the utilization efficiency of crude fiber in growing pigs increased significantly(P < 0.05).The content of digestible dry matter and protein in whole-plant corn could be significantly different with different starch properties and uses(P < 0.05).The content of digestible dry matter was higher and digestible protein content was lower when starch property was gelatin,and when corn was used for red grain,the content of digestible dry matter was higher and the content of digestible protein was lower when starch was gelatin.The content of digestible protein in whole-plant corn is the highest,and the content of digestible and dry matter can be digestible when used in feed.Compared with other varieties,the digestible nutrients and effective yield per mu of red grain maize were the highest.The dynamic changes of mycotoxins in maize and its whole plant were tested.The results showed that the content of mycotoxin in maize at different harvest periods was in accordance with the national feed hygiene standard(GB13078-2017),and the whole-plant corn was stored for 0 week.Aflatoxin B1,fumatoxin(B1+B2),deoxynivalenol and zeaxylenone were not detected,and stored for 6 weeks,10 weeks and 42 weeks,respectively.Mycotoxins were still not detected in the three regions,and the mildew corn seeds in all three regions were in accordance with the national feed hygiene standard(GB13078-2017),while the mildew of corn seeds was more serious in the northwest plain of Shandong Province.To sum up,the whole-plant corn silage could be stably preserved after 42 days,and therewas no significant difference in nutrient composition and total energy before and after silage,and the whole-plant corn silage did not decrease the content of nutrients,and the stable time of silage was different.The storage method of the whole-plant corn without adding bacteria is enough to meet the safety standard of feed in China;the content of nutrients does not change greatly because of the addition of bacteria;the three-way crossbred pig can utilize the nutrients of the whole corn.The nutrient utilization of whole corn was affected by different varieties or adding proportion of whole-plant corn,and the detection rate of partial toxin in maize was much lower than that in seed,and the yield was to green at milk-ripe stage.After42 weeks of storage and storage,4 species were below the detection line,and 4 weeks after harvest,the appearance of non-moldy seed toxins were all lower than the national standard.The excess rates of aflatoxin B1 and zearalenone were 20% and 33%,respectively.The whole-plant corn silage at milk stage was fed to live pigs.Mycotoxin can be completely controlled below the national standard.The dry process of seed harvest is the main link of mycotoxin contamination. |
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