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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #133743
Title: RELATIONSHIP BETWEEN SERUM CONCENTRATIONS OF LEPTIN AND CARCASS COMPOSITION AND QUALITY IN BEEF CATTLE AND SWINE

Author
item MCFADIN, E - UNIV OF MISSOURI
item Geary, Thomas
item Macneil, Michael
item KEISLER, D - UNIV OF MISSOURI
item BERG, E - UNIV OF MISSOURI

Submitted to: American Meat Science Association Conference Reciprocal Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2003
Publication Date: 7/1/2003
Citation: MCFADIN, E.L., GEARY, T.W., MACNEIL, M.D., KEISLER, D.H., BERG, E.P. RELATIONSHIP BETWEEN SERUM CONCENTRATIONS OF LEPTIN AND CARCASS COMPOSITION AND QUALITY IN BEEF CATTLE AND SWINE. AMERICAN MEAT SCIENCE ASSOCIATION CONFERENCE RECIPROCAL PROCEEDINGS. 2003. Poster available at: http://www.meatscience.org/pubs/rmcarchv/2002/presentations/rmc_2002_055_3_0000_McFadin.pdf.

Interpretive Summary: The protein hormone product of the ob gene, leptin, has been implicated in the control of food intake and body composition. The principal site of leptin production is the adipocyte, and circulating concentrations of leptin have been positively correlated with body fat mass in humans and rodents, with limited data available in other species. Recently, four investigations were conducted to evaluate the relationship between circulating concentrations of leptin and carcass composition and quality in beef cattle and swine. Our objectives were to determine if circulating levels of leptin were indicative of beef and pork carcass quality and composition and to determine the composition and quality factors which significantly correlated with serum levels of leptin. The beef studies consisted of 3 investigations. Two of the studies were conducted at Miles City, MT with two groups of crossbred steers and heifers managed under feedlot conditions. The first group (Beef 1), consisted of 88 ½Red Angus, ¼Charolais, and ¼Tarentaise composite steers and the second group (Beef 2), consisted of 91 F2 steers and heifers born to Limousin, Hereford, or Piedmontese by Beef 2 F1 cows crossed to F1 bulls of similar genetic makeup. Beef 1 and Beef 2 cattle were harvested between 14 and 17 months of age with an average hot carcass weight (HCW) of 293.9 and 276.9 ± 3.4 kg, respectively. A third group of cattle in this investigation consisted of steers (average HCW = 343.9 ± 3.6 kg) entered into the 2001 Missouri State Beef carcass contest (Beef 3), which represented various genotypes, raised under diverse management conditions. The swine study consisted of single survey of 310 barrows and gilts entered in the 2000 National Barrow Show Sire Progeny Test (Pork 1). Breeds were Berkshire (n = 138), Chester White (n = 37), Duroc (n = 40), Landrace (n = 27), Poland China (n = 26), and Yorkshire (n = 42). Serum samples were collected from pigs upon entry on test (approximately 34 kg BW) and again 24 h prior to harvest (approximately 111 kg BW). Serum concentrations of leptin from cattle and swine were determined using a heterologous leptin radioimmunoassay validated for use in these and other species in our lab. All beef and pork carcass data measurements were collected by trained personnel. Serum concentrations of leptin at harvest were significantly correlated with subcutaneous back fat thickness (r = 0.34 to 0.51; P < 0.01) and marbling score (r = 0.10 to 0.50; P < 0.06) across all four studies. In Beef 2 and Pork 1, circulating concentrations of leptin were negatively correlated with ribeye area (r = -0.45 and -0.30, respectively; P < 0.001) however, this relationship did not exist in either Beef 1 or Beef 3. In Beef 1 and Beef 2, kidney, pelvic, and heart scores were significantly correlated with serum concentrations of leptin (r = 0.42 and 0.56; P < 0.001) however, this relationship was not found to exist in the Beef 3 investigation. In Beef 1, Beef 2, and Beef 3, carcass yield grade was associated with leptin (r = 0.19, 0.52, and 0.19, respectively; P < 0.10). In Pork 1, Berkshire pigs had greater serum concentrations of leptin (6.93 ng/ml) than all breeds (P < 0.05) except Poland China (6.80 ng/ml) at harvest. Barrows had greater serum concentrations of leptin than did gilts (6.83 and 3.71 ng/ml; P < 0.001). Further research is necessary to determine if leptin may be used in conjunction with other measurements to predict live animal carcass composition.

Technical Abstract: The protein hormone product of the ob gene, leptin, has been implicated in the control of food intake and body composition. The principal site of leptin production is the adipocyte, and circulating concentrations of leptin have been positively correlated with body fat mass in humans and rodents, with limited data available in other species. Recently, four investigations were conducted to evaluate the relationship between circulating concentrations of leptin and carcass composition and quality in beef cattle and swine. Our objectives were to determine if circulating levels of leptin were indicative of beef and pork carcass quality and composition and to determine the composition and quality factors which significantly correlated with serum levels of leptin. The beef studies consisted of 3 investigations. Two of the studies were conducted at Miles City, MT with two groups of crossbred steers and heifers managed under feedlot conditions. The first group (Beef 1), consisted of 88 ½Red Angus, ¼Charolais, and ¼Tarentaise composite steers and the second group (Beef 2), consisted of 91 F2 steers and heifers born to Limousin, Hereford, or Piedmontese by Beef 2 F1 cows crossed to F1 bulls of similar genetic makeup. Beef 1 and Beef 2 cattle were harvested between 14 and 17 months of age with an average hot carcass weight (HCW) of 293.9 and 276.9 ± 3.4 kg, respectively. A third group of cattle in this investigation consisted of steers (average HCW = 343.9 ± 3.6 kg) entered into the 2001 Missouri State Beef carcass contest (Beef 3), which represented various genotypes, raised under diverse management conditions. The swine study consisted of single survey of 310 barrows and gilts entered in the 2000 National Barrow Show Sire Progeny Test (Pork 1). Breeds were Berkshire (n = 138), Chester White (n = 37), Duroc (n = 40), Landrace (n = 27), Poland China (n = 26), and Yorkshire (n = 42). Serum samples were collected from pigs upon entry on test (approximately 34 kg BW) and again 24 h prior to harvest (approximately 111 kg BW). Serum concentrations of leptin from cattle and swine were determined using a heterologous leptin radioimmunoassay validated for use in these and other species in our lab. All beef and pork carcass data measurements were collected by trained personnel. Serum concentrations of leptin at harvest were significantly correlated with subcutaneous back fat thickness (r = 0.34 to 0.51; P < 0.01) and marbling score (r = 0.10 to 0.50; P < 0.06) across all four studies. In Beef 2 and Pork 1, circulating concentrations of leptin were negatively correlated with ribeye area (r = -0.45 and -0.30, respectively; P < 0.001) however, this relationship did not exist in either Beef 1 or Beef 3. In Beef 1 and Beef 2, kidney, pelvic, and heart scores were significantly correlated with serum concentrations of leptin (r = 0.42 and 0.56; P < 0.001) however, this relationship was not found to exist in the Beef 3 investigation. In Beef 1, Beef 2, and Beef 3, carcass yield grade was associated with leptin (r = 0.19, 0.52, and 0.19, respectively; P < 0.10). In Pork 1, Berkshire pigs had greater serum concentrations of leptin (6.93 ng/ml) than all breeds (P < 0.05) except Poland China (6.80 ng/ml) at harvest. Barrows had greater serum concentrations of leptin than did gilts (6.83 and 3.71 ng/ml; P < 0.001). Further research is necessary to determine if leptin may be used in conjunction with other measurements to predict live animal carcass composition.