| The objective of this research is to study the muscle growth and development rule of Rongchang and Landrace×Rongchang pigs, to reveal key role of nutrition in controlling meat growth and development, and further provide references for studying the interaction of nutrition and function genes of meat quality, which is expressed by level of cell and molecule, and to provide basis for the revision of feeding standardsThis experiment selected ninety Rongchang pigs and Landrace×Rongchang pigs respectively which is 8kg.Each breed slaughter 6 pigs at 10kg, amd others were randomly divided into two groups with two feeding standard(one group fed Feeding standard for Rongchang pigs (standard one) while the other fed China Feeding standard for lean-type pigs(standard two),),Each group had six duplicates with seven swines,and all was 92 swines. One pig in each duplicates was slaughter at 20kg, 35kg, 50kg, 80kg and 110kg (Rongchang pig of 100kg) respectively.The results revealed:(1) With the increase of body weight, both Landrace×Rongchang and Rongchang pigs showed the tendency of ascending firstly and then declining in daily gain, both biggest at 35kg-50kg. Two genetics were continual rising in F/G, after 50kg F/G was significantly bigger than before 50kg.(2) With the increase of body weight, both genetics showed ascending tendency in slaughtering rate, three-point and 6-7 rib fat thickness and LM area.While the lean percentage showed no apparent change rules. In the feeding standard for Rongchang pigs: Slaughter rate for Rongchang pigs gained quickly at 35-50kg and 50-80kg(P＜0.05),while Landrace×Rongchang rose more significantly during 10-20kg,20-35kg and 50-80kg.(P＜0.01). Rongchang pig's three-point fat thickness grew quickly after 20kg(P＜0.05),and more significantly during 80-100kg(P＜0.01), Landrace×Rongchang three-point fat thickness grew quickly during 20-35kg(P＜0.05),and more significantly rose each stage during 35-80kg(P＜0.01).Rongchang pigs' 6～7 rib fat thickness grew remarkably during 20-5kg,35-50kg and 80-100kg (P＜0.01), while Landrace×Rongchang grew quickly during 10-20kg(P＜0.05) and increased more significantly during 35-50kg and 50-80kg (P＜0.01). Rongchang pigs' LM area increased more significantly during 20-35kg and35-50kg(P＜0.01), while Landrace×Rongchang LM area increased slowly during 35-50kg,and fast during 10-20kg(P＜0.05),other stages increased more significantly(P＜0.01). In China feeding standard for lean-type pigs: The slaughter rate of Rongchang pigs grew fast during 20-35kg(P＜0.05),and more fast during 50-80kg(P＜0.01),while Landrace×Rongchang rose more significantly during 10-20kg and 35-50kg(P＜0.01). Rongchang pig's three-point fat thickness grew more significantly during 20-35kg,35-50kg and 80-l00kg(P＜0.01), Landrace×Rongchangs rose fast during 20-35kg, during 50-80kg and 80-110kg increased more significantly-Rongchang pig's 6～7 rib fat thickness grew more significantly during20-35kg and 50-80kg(P＜0.01 ),and significantly during 80-100kg(P＜0.05),while Landrace×Rongchang rose more significantly during 10-20kg,35-50kg and80-110kg.(P＜0.01).LM area of Rongchang pigs increased more significantly during 20-35kg(P＜0.05),while Landrace×Rongchangs increased fast each stage(P＜0.05), especially during 20-35kg,50-80kg and 80-110kg(P＜0.01).(3) The muscle pH1, pH24, muscle color (including Minolta L*,a,b value) of Rongchang and Landrace×Rongchang had no significant growth development. Marbling scores of two genetics increased parabolically with the increase of body weight. Marbling scores of Rongchang pigs increased more significantly during 10-20kg and 50-80kg,(P＜0.01).while Landrace×Rongchang increased more significantly during 10-20kg,20-35kg and 50-80kg(P＜0.01).Drop loss of Rongchang pigs at 80kg and 100kg were significantly bigger than 10kg(P＜0.05).In China feeding standard for lean-type pigs: Marbling scores of Rongchang pigs increased more significantly during 10-20kg,20-35kg and 50-80kg(P＜0.01),and significantly during 80-100kg(P＜0.05), Landrace×Rongchang increased fast during 10-20kg,35-50kg(P<0.05),and more fast during 20-35kg and 50-80kg(P＜0.01).In feeding standard for Rongchang pigs: The drop loss of LM from Rongchang pigs significantly decreased during 50-80kg,and highest at 10kg,and lowest at 80kg. While Landrace×Rongchang pigs drop loss decreased significantly during 20-35kg and 35-50kg, the drop loss was highest 35kg and lowest 110kg.In China feeding standard for lean type pigs:The drop loss of Rongchang pigs at 10kg was more significantly higher than 20kg,and significantly higher than 50kg and 80kg,other had no significantly.The highest was highest at 10kg, and lowest at 20kg. Landrace×Rongchangpigs' drop loss was highest at 20kg and lowest at 110kg,and more significantly between these stgages.(4) With body weight increased, muscle fiber diameter increased while density decreased. In feeding standard for Rongchang pigs: Muscle fiber diameter of Rongchang pigs rose more significantly during 20-35kg and 80-100kg(P＜0.01), and muscle fiber density decreased more remarkably during 10-20kg and 20-35kg. Landrace×Rongchang muscle fiber diameter increased more significantly during 10-20kg (P＜0.01), and significantly increased during 35-50kg (P＜0.05), muscle fiber density of Landrace×Rongchanghad more significantly decreased during 10-20kg (P＜0.01)and significantly declined at 35-50kg (P＜0.05).In the China feeding standard for lean-type pigs, Muscle fiber diameter of Rongchang pigs rose significantly during 10-20kg and 80-100kg(P＜0.05) and more significantly during 20-35kg(P＜0.01), while muscle fiber density decreased more significantly during 10-20kg and 20-35kg(P＜0.01).The muscle fiber diameter of Landrace×Rongchang grew more significantly during 10-20kg(P＜0.05),and significantly during 50-80kg(P＜0.01),while muscle fiber density increased more significantly during 10-20kg and 50-80kg(P＜0.01).(5) With the development of body weight, DM in these two genetics LM increased while free water declined. The content of crude protein of LM from two genetics ascended firstly and then declined, and Rongchang pigs went to top at 50kg,while Landrace×Rongchang at 80kg.With the development of body weight,the EE of LM from two breeds increased. There was no certain growth development in CA.In feeding standard for Rongchang pigs:The musculus longissimus dorsi DM of Rongchang pig increased more significantly during 20-35kg and 80-100kg phases (P＜0.01), while free water declined significantly during these stages. The content of DM from Landrace×Rongchang increased more significantly during 20-35kg(P＜0.01), while free water declined significantly at the same stage. The content of CP from Rongchang pigs increased more significantly during 20-35kg(P＜0.01) while Landrace×Rongchang, increased more significantly during 35-50kg(P＜0.01),and significantly 50-80kg(P＜0.05). The content of EE from Rongchang pigs rose significantly during 20-35kg(P＜0.05),and more significantly during 80-100kg(P＜0.01),while Landrace×Rongchang grew fast dirng 20-35kg(P＜0.01).In China feeding standard for lean-type pigs:The growth development of DM and free water from two genetics were the same to the feeding standard for Rongchang pigs,and the same to the content of Rongchang pigs crude protein,while the content of CP from Landrace×Rongchang's LM increased more significantly during 20-35kg and 50-80kg(P＜0.01). The content of EE from two genotypes declined slowly during 10-20kg,ascended slowly during 20-80kg each stage,rhen Landrace×Rongchang grew slowly,while Rongchang pigs grew fast(P＜0.01).(6) In this study, we found there were no significant effect on Rongchang pig and Landrace×Rongchang carcass character, meat quality and LM nutrition composition between these two feeding standard. Contrast with the feeding standard for Rongchang pigs,the China feeding standard for lean-type pigs could significantly decrease Rongchang pigs daily gain during 80-100kg(P＜0.01),and significantly increased Rongchang pigs' F/G at the same stage(P＜0.01). There were no significantly effect on Landrace×Rongchang production performance between these two feedine standard(P＞0.05).
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