| Maize is one of the three major grain crops planted in China,but most of the corn straw has not been used efficiently,resulting in low utilization rate of agricultural by-products.Therefore,it is necessary to improve the added value of agricultural by-products and the comprehensive utilization rate of resources.Corn straw is beneficial to animal digestion and absorption after bio-fermentation.As a typical monogastric animal,pigs have developed cecum and colon.A large number of microorganisms in cecum and colon play an important role in the utilization of fibers.Maintaining a certain proportion of crude fiber in diet can regulate the nutrient absorption of intestinal tract and strengthen the immune function of intestinal tract.Feeding live pigs with whole corn silage can not only make use of corn straw resources and reduce environmental pollution caused by incineration,but also reduce the cost of feeding live pigs.At present,it is common to use whole-plant corn silage as feed for cattle,sheep and other herbivorous livestock,but there are few reports about its replacement for pig diet.The purpose of this experiment was to study the effects of different ratios of whole-plant corn silage on growth performance,nutrient digestion and absorption,fecal flora number,slaughter performance and visceral organ development of growing-finishing pigs,and to provide theoretical basis for the promotion of whole-plant corn in pig production.The experiment was divided into two stages.The growth pigs is 20 ~ 60 kg growing pigs;the fattening pigs 60 ~ 140 kg fattening pigs.At each stage,240 pigs with similar weight were randomly divided into 4 treatments,3 replicates for each treatment and 20 pigs for each replicate.The pre-feeding period was 7 days,the growth pigs was 72 days,and the total silage maize addition was 0,20,30 and 40% respectively.The fattening pigs was 91 days,and the total silage maize addition was 0,30,40 and 50% respectively.The results shown that in the growth pigs,the whole plant corn silage diet had significant effects on the final weight,daily feed intake(feeding and dry matter basis),daily gain and feed weight ratio(feeding and dry matter basis)of growing and finishing pigs(P<0.05).With the increase of the proportion of whole plant corn silage in the diet,the daily feed intake and dry matter intake increased significantly,the daily gain decreased significantly(P<0.05),and the proportion of feed base material had no significant effect(P>0.05),but the proportion of dry matter base material in40% supplementation group was significantly higher than that in control group and 20% and30% supplementation group(P<0.05).In the growth-fattening pigs,the whole plant cornsilage diet had significant effects on the final weight,daily feed intake(feeding basis and dry matter basis),daily gain and feed-Weight ratio(feeding basis and dry matter basis)of growing-finishing pigs(P < 0.05).With the increase of the proportion of whole plant corn silage in the diet,the basic daily feed intake and dry matter daily feed intake increased significantly(P < 0.05),the daily gain decreased significantly,and the feed-to-weight ratio(feeding and dry matter basis)increased significantly.The feed-to-weight ratio of 50%supplementation group was significantly higher than that of control group and 30% and 40%supplementation group(P<0.05).In the growth pigs,the apparent digestibility of dry matter,energy,organic matter and crude protein of growing-finishing pigs was significantly affected by whole-plant corn silage diet(P<0.05).The apparent digestibility of dry matter,energy,organic matter and crude protein decreased significantly with the increase of the proportion of whole plant corn silage in the diet,which was significantly lower in the supplementation group than in the control group(P < 0.05).In the growth-fattening pigs,the apparent digestibility of dry matter,energy,organic matter and crude protein of growing-finishing pigs was significantly affected by whole-plant corn silage diet(P<0.05).The apparent digestibility of dry matter,energy,organic matter and crude protein decreased significantly with the increase of the proportion of whole plant corn silage in the diet,which was significantly lower in the supplementation group than in the control group(P < 0.05).In the growth pigs,whole-plant corn silage diet had significant effects on energy metabolism rate,net protein utilization rate and protein biological value of growing-finishing pigs(P<0.05).The energy metabolism rate,net protein utilization rate and biological value of protein decreased significantly with the increase of the proportion of whole plant corn silage in the diet.The40% group was significantly lower than the control group and the 20% and 30% group(P<0.05).Similarly,in the growth-fattening pigs,the whole plant corn silage diet had significant effects on energy metabolism rate,net protein utilization rate and protein biological value of growing-finishing pigs(P<0.05).The energy metabolism rate,net protein utilization rate and biological value of protein decreased significantly with the increase of the proportion of whole plant corn silage in the diet.The 50% group was significantly lower than the control group and the 30% and 40% group(P<0.05).In the growth pigs,the total number of acid-producing bacteria and coliform bacteria in growing-finishing pigs were significantly affected by the whole corn silage diet(P<0.05).With the increase of the proportion of corn silage,the total number of acidogenic bacteria and coliform bacteria increased significantly(P < 0.05).Similarly,in the growth-fattening pigs,the total number of acid-producing bacteria and coliform bacteria in growing-finishing pigs were significantly affected by the whole corn silage diet(P < 0.05).The total bacterial count of acid-producing bacteria and coliform bacteria decreased significantly with the increase of the proportion of whole corn silage in the diet(P< 0.05).The whole plant corn silage diet had significant effects on slaughter weight,carcass weight,slaughter rate,fat meat rate,proportion of plate oil,straight carcass length,oblique carcass length,back fat thickness,eye muscle area and skin thickness of growing and finishing pigs(P<0.05).The slaughter weight,carcass weight,slaughter rate,fat percentage,plate oil ratio,carcass straight length,carcass oblique length,back fat thickness,eye muscle area and skin thickness decreased significantly with the increase of the whole corn silage addition ratio in the diet,and the 50% addition group was significantly lower than the control group(P < 0.05).The whole plant corn silage diet had no significant effect on moisture,protein,fat and ash content in muscle of growing-finishing pigs(P>0.05).The whole-plant corn silage diet had no significant effect on the development of heart,lung,liver,spleen,kidney,small intestine and large intestine of growing-finishing pigs(P > 0.05),but had significant effect on stomach(P<0.05).The weight of stomach in 50% supplementation group was significantly higher than that in control group and 30% and 40% supplementation group(P<0.05).To sum up,using 30% milk mature whole plant silage maize to replacing the basic diet of growing pigs(20-60 kg)and using 40% milk mature whole plant silage maize to replacing the basic diet of fattening pigs(60-140 kg)had no adverse effects on the production performance of pigs.Therefore,the proportion of 30% is quite feasible to replace the basic diet of growing pigs(20-60 kg)and the proportion of 40% is quite feasible to replace the basic diet finishing pigs(60-140 kg)by using milk mature whole plant silage maize. |
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