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This Article Full Text Full Text (PDF) All Versions of this Article: jas.2008-1268v1 87/10/3069    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Hoque, M. A. Articles by Suzuki, K. PubMed PubMed Citation Articles by Hoque, M. A. Articles by Suzuki, K.

Genetic associations of residual feed intake with serum insulin-like growth factor-I and leptin concentrations, meat quality, and carcass cross sectional fat area ratios in Duroc pigs¹

M. A. Hoque^*,,2, K. Katoh and K. Suzuki^*

^* Laboratory of Animal Breeding and Genetics, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai, 981-8555, Japan; and Department of Animal Breeding and Genetics, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; and Laboratory of Animal Physiology, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai, 981-8555, Japan

² Corresponding author: azharhoque{at}yahoo.com

Genetic relationships of measures of residual feed intake and daily feed intake with serum IGF-I concentrations at 8 wk of age and at 105 kg of BW, serum leptin concentration at 105 kg of BW, meat quality, and different fat accumulation traits on 834 Duroc pigs in 7 generations were estimated. Two measures of residual feed intake were estimated from the differences between actual and predicted feed intake: phenotypic residual feed intake (RFI_phe) and nutritional residual feed intake (RFI_nut). Meat quality traits included drip loss, cooking loss, pork color score, pork lightness (L*), and pH, whereas fat accumulation traits were subcutaneous fat, intermuscular fat, and total fat percent at 5-6th thoracic vertebra; subcutaneous fat, intermuscular fat, abdominal fat, and total fat percent at one-half body length and at last thoracic vertebra, and seam fat score. The IGF-I concentrations at 8 wk of age and 105 kg of BW had weak genetic correlations with measures of residual feed intake and daily feed intake (absolute values ranging from 0.14 to 0.24). The genetic correlations between measures of residual feed intake and serum leptin concentration were strong and positive (r_g with RFI_phe and RFI_nut were 0.74 and 0.80, respectively). Residual feed intake was moderately but negatively correlated with cooking loss (r_g with RFI_phe and RFI_nut were –0.42 and –0.49, respectively), whereas daily feed intake was moderately and positively correlated with drip loss and pH (0.33 and 0.36, respectively). Daily feed intake was also moderately correlated with subcutaneous fat accumulations at the 5-6th thoracic vertebra (0.31) and one-half body length (0.31) regions and was strongly correlated with accumulations at the last thoracic vertebra region (0.57). The genetic correlations between daily feed intake and intermuscular fat accumulations at all of the carcass sites were strong (0.60, 0.76, and 0.56 for intermuscular fat at 5-6th thoracic vertebra, one-half body length, and last thoracic vertebra, respectively). Residual feed intake was strongly and positively correlated with all of the fat accumulation traits (ranging from 0.53 to 0.88). The results indicate that reducing residual feed intake (increased efficiency) would lead to increased cooking loss and darkness, and decreased serum leptin concentration, fat accumulations at the different sites, and seam fat at the 6th rib interface of pork carcasses.

Key Words: carcass trait • fat accumulation • genetic relationship • hormone trait • performance trait