| Miniature pigs have irreplaceable advantages in genetic breeding,growth and development,and disease models,especially in biomedical and cardiovascular system research.However,at present,there is no unified standard for the feeding of miniature pigs as experimental animals.In order to prevent the excessive weight of miniature pigs due to overfeeding,many studies have been carried out to obtain the ideal body size of miniature pigs by restrict feeding.The study on pigs’ dietary restriction behavior is a systematic study on their nutritional restriction,and its significance is to deeply analysis of the effects of dietary restriction on growth performance,metabolic characteristics and behavioral habits of pigs.The study of behavioral characteristics of pigs has important theoretical value and practical significance for pig management and feeding,disease prevention and control,which also contributes to promote the standardization the feeding of experimental animals,improving animal welfare and optimizing production management.For this reason,this study utilized Banna miniature inbred lines as the research object to investigate the effects of different feeding restrictions on its behavior.Before starting experiment,a total of 18 pigs were selected and divided into three groups according to body weight and sex: Control group,70% diet feeding group and 40%diet feeding group,with half male and half female in each group.Experiments were conducted at four phases: an ad libitum feeding phase(first phase),a restricted feeding phase(second phase),a behavioral measurement phase during restricted feeding(third phase)and a return to ad libitum feeding phase(fourth phase).The determination of body weight changes before and after feeding and the average daily feed intake(recording the daily feeding amount and remaining feed)of different experimental groups were obtained at each stage.The line chart drawn from image analysis and counting the total time and total frequency of each behaviour occurring daily in each of the four phases in the different experimental groups was used to compare the differences in daily behaviours such as walking,exploring,sleeping and drinking that occurred in each phase.In the third stage,the effects of feeding restriction on the sexual behavior of boars were evaluated by measuring their courtship behavior and the preparation time before climbing and crossing.Foraging behavior and the number of buried feed points found after feeding were measured from 10:00 to 17:00 in all experimental groups,and the effects of feed restriction on feeding behavior of Banna miniature inbred lines were evaluated.In the fourth stage,the feed intake of 0-15 min,16-30 min and 31-60 min after feeding was measured to further compare the feeding rate in each period.The results of the experimental analysis showed as follows:(1)the behavior determination of the ad libitum group,the 70% diet group,and the 40% diet group under restricted feeding(the second stage)and the restricted feeding situation(the third stage)was compared.The frequency of walking behavior and drinking behavior of the inbred line of Banna miniature pigs under the feed restriction decreased,while the frequency of exploration behavior increased as compared with the ad libitum feeding group.The results of daily average feed intake measurement showed a significant difference(P<0.05)between the sows in the 70% diet feeding group during the ad libitum feeding phase(first phase)and the recovery feeding phase(fourth phase),while there was no significant difference(P>0.05)among boars except for the difference in feed intake caused by artificial control of feed amount.Banna miniature pig inbred sows had lower foraging behavior scores than boars under restricted feeding conditions,indicating that boars have a greater demand for feed than sows during the rapid growth stage,and are more active and more sensitive to react to changes the external environment.(3)Under the condition of feeding 40% of the diet,both boars and sows can find the burying point,indicating that when the feeding limit is too high,it will increase their exploration behavior and look for food to satisfy their hunger.In this experiment,it was found that the inbred line of Banna miniature pigs had the fastest feed intake rate in the time period of 0-15 minutes,and the feed intake rate of sows fed with 70% diet was significantly different from that of the control group(P<0.05).In addition,after four stages of experiments in this study,the body weight of the Banna miniature pig inbred line of both male and female in the control group showed an upward trend,while the body weight of the experimental pigs in the 40% diet group was relatively stable during the period.(4)When a boar is tested against a sow in heat experiment,its response score increases with the number of tests,but the preparation time required before mounting decreases as the number of tests increases and it shows that the preparation time for mounting at 10:00 in the morning is shorter than that at 16:00 in the afternoon.These results showed that the boar’s libido was relatively stronger in the morning,which was conducive to the smooth development of artificial semen collection.In conclusion,this study evaluated the effects of ad libitum feeding,70% diet feeding and 40% diet feeding on the weight,daily behavior,feeding behavior and sexual behavior of male and sows of Banna miniature inbred line.It was observed that restricted feeding,especially 40% diet feeding,turn boar lazy to explore the feed,so as to find more food to satisfy hunger and reduce the stimulus of hunger.Sows,on the other hand,reduce the frequency of each behavior and maintain more energy.This study is a powerful supplement to the existing research system on issues related to miniature pig animal experimentation,and to a certain extent,makes up for the lack of systematic research on the feeding restriction behavior of inbred lines of Banna miniature pigs.In order to formulate its feeding standards,to explore reasonable feeding environment and feeding methods while taking into account animal welfare provide theoretical reference and technical support. |
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