Study On The Selection And Breeding Of The First-generation Xiangling Pigs

Xiangling pig is a new breed by using the crossbred fixing after hybridizing of Shaziling pig and Berkshire pig,and now still under being generation bred.In order to study the breeding progress of the first-generation Xiangling pigs,the reproductive performance of29 Xiangling sows was statistically investigated.A total of 80 pigs,including Xiangling pigs,Shaziling pigs,（Berkshire×Shaziling）×Shaziling（abbreviated as BSS）pigs,and Shaziling×（Berkshire×Shaziling）（abbreviated as SBS）pigs,20 pigs of each breed,half male and half female,were selected for feeding experiment.After 14 weeks,6 Xiangling pigs,4Shaziling pigs,4 BSS pigs,and 4 SBS pigs were randomly selected for slaughter,and their growth and fattening performance,carcass traits,meat quality,and nutritional components were measured and analyzed.The results are as follows:（1）The results of reproductive performance:The total litter size of Xiangling sows was11.17±2.99,the live litter size was 10.34±2.54,the birth litter weight was 13.39±3.38 kg,and the weaning litter weight was 35.32±9.88 kg.（2）The results of growth and fattening performance:The Xiangling pigs had the highest values（P<0.05）of body weight,body length,body height,chest circumference,chest width,and chest depth.The SBS pigs had the largest abdominal circumference,followed by the Xiangling pigs,and there was no significant difference between them（P>0.05）.The average daily weight gain of Xiangling pigs(556.18±86.09 g·d^-1)was higher（P<0.01）than that of Shaziling pigs,BSS pigs,and SBS pigs by 135.51 g·d^-1,110.21 g·d^-1,and 89.03 g·d^-1,respectively.The feed to weight gain ratio from low to high was Xiangling pigs（3.83:1）,BSS pigs（3.90:1）,SBS pigs（3.93:1）,and Shaziling pigs（4.08:1）.（3）The results of carcass traits:There were no significant differences in slaughter rate,average three-point skin thickness,and skin rate among the groups（P>0.05）.Shaziling pigs had the lowest pre-slaughter weight（83.43±3.71 kg）.The carcass weights of Xiangling pigs and SBS pigs were significantly higher（P<0.01）than that of Shaziling pigs.The loin-eye area of Xiangling pigs was the highest（25.16±5.55 cm²）,which was 5.63 cm² higher（P<0.05）than that of Shaziling pigs.The average fat thickness at three points of Xiangling pigs was the lowest（32.20±3.80 mm）,which was 6.40 mm lower（P<0.05）than that of SBS pigs.Xiangling pigs had the longest carcass length（90.92±1.80 cm）,the highest lean meat rate（46.79±1.82%）,and the lowest fat rate（27.74±2.75%）.（4）The results of meat quality:The data of muscle quality index of the test pigs measured in the 4 groups were all within the normal range.There was no significant difference in the marbling grade score,p H_1h,p H_24h,L_1h,a_24h,b_24h,water loss rate,and storage loss（P>0.05）.The order of meat color score from high to low was the SBS pigs,Shaziling pigs,Xiangling pigs,and BSS pigs.The a_1h value of the Xiangling pigs（5.03±0.48）was significantly higher（P<0.01）than that of BSS pigs（3.70±0.05）.The b_1hvalue from low to high was Shaziling pigs,SBS pigs,BSS pigs,and Xiangling pigs.The L_24hvalue of BSS pigs（43.16±6.15）was the largest,while that of Shaziling pigs（36.75±2.67）was the smallest.The smallest shear stress was in SBS pigs（6.42±1.69 N）and the largest in BSS pigs（14.15±4.83 N）.The rate of cooked meat of the Xiangling pigs（64.19±1.87%）was significantly lower（P<0.05）than that of SBS pigs（68.99±4.13%）.（5）Analysis of meat nutritional components:The crude protein content of the Xiangling pigs was lower（P<0.05）than those of Shaziling pigs and BSS pigs,and their intramuscular fat content was lower（P<0.01）than that of SBS pigs.There was no significant difference in the contents of Ca,Zn,Cu,Mg,and Mn amongthe four groups（P>0.05）.There were no significant difference in K content among the Xiangling pigs,Shaziling pigs,and BSS pigs（P>0.05）.The Na content of the Xiangling pigs was higher（P<0.01）than that of SBS pigs.The residues of heavy metals Pb,Cd,As,and Hg in the longissimus dorsi muscle of the four groups did not exceed the standard.There were no significant difference in inosinic acid among the four groups（P>0.05）.The contents of Asp,Thr,Glu,Gly,Ala,Leu,Tyr,and Pro in Xiangling pigs were not significantly different from those in the other three groups（P>0.05）.The contents of Phe,Lys,and His in Xiangling pigs were significantly lower（P<0.05）than those of BSS pigs.The content of palmitic acid in Xiangling pigs was the lowest,no significant difference from other groups（P>0.05）.The content of heptadecanoic acid in Xiangling pigs was higher（P<0.05）than that of SBS pigs.The contents of elaidic acid,linoleic acid,and arachidonic acid in Xiangling pigs were higher than those of other three groups,but the difference was not significant（P>0.05）.The content of arachidic acid in Xiangling pigs was significantly lower（P<0.05）than those of SBS pigs and BSS pigs.The content ofα-linolenic acid in Xiangling pigs was significantly higher（P<0.05）than those of SBS pigs and BSS pigs.To sum up,the first-generation Xiangling pigs had achieved ideal breeding results in terms ofreproductive performance,growth and fattening performance,carcass traits,meat quality,nutrients and flavor substances.This study can provide data reference and technical support for the breeding of subsequent generations of Xiangling pigs,and also provide breeding ideas and methods for new varieties of other pigs.