SUMMARY
Effect of selection for lean growth efficiency on growth
performance, nutrient digestibility, blood profile, and carcass
and meat quality.
Fabian, J., L. I. Chiba, D. L. Kuhlers, L. T. Frobish,
K. Nadarajah, W. H. McElhenney, J. Lin, and B. L. Anderson.
Eight select line (SL) and eight control line (CL) Duroc
pigs were used to determine the effect of six generations of
selection for lean growth efficiency on growth performance,
nutrient digestibility, serum profiles, and carcass and meat
quality. At 20 kg, pigs were placed in pens individually. Three
corn-soybean meal diets [grower (G), finisher 1 (F1), and finisher
2 (F2)] were formulated to meet the NRC nutrient requirements.
Pigs were allowed ad libitum access to feed and water. At the
end of the G and F2 phases pigs were fed diets containing 0.25
% Cr2O3 to determine apparent digestibility
of CP and DM. Three blood samples were taken from each pig
at 20, 50 and 105 kg for glucose, triglyceride (TG), and urea
N (BUN) analyses. Pigs were subjected to ultrasound backfat
(UBF) measurement at 50 kg and at the end. At 105 kg, each
pig was slaughtered.
The SL pigs grew faster and more efficiently
(P < 0.05) during
G (ADG: 812 vs 733 g/day; G/F: 429 vs 402 g/kg) and the F1
phases (ADG: 931 vs 804 g/day; G/F: 330 vs 296 g/kg), but there
was no effect of line during the F2 phase and overall. The
SL pigs had lower UBF (P < 0.05) at 50 (7.15 vs 9.04 mm) and
105 kg (17.59 vs 22.89 mm), and had higher initial serum TG
(5.49 vs 3.23 mg/L; P < 0.001) and lower initial BUN (0.95
vs 1.17 mg/L; P < 0.05) than the CL pigs. The SL pigs had heavier
heart (342 vs 298 g; P < 0.05), liver (1459 vs 1359 g; P =
0.08), and kidneys (298 vs 249 g; P < 0.01). Lower 10th rib
backfat (21.66 vs 31.62 mm; P < 0.01) and larger longissimus
muscle area (32.84 vs 30.02 cm2; P = 0.1) were reflected
in higher estimate daily lean gain (279 vs 238 g/day; P < 0.01)
in the SL pigs. The SL pigs had lower meat color (2.02 vs 2.29;
P < 0.05), firmness (2.45 vs 3.23; P < 0.01), and marbling
(2.82 vs 3.55; P < 0.1) scores.
These results indicate that selection for lean growth efficiency
has changed the growth rate and body composition of the SL
pigs.
Built: 5/01/01 |
