Abstract
Hydrolyzed Feather Meal as a Source of Amino Acids for Finisher
Pigs.
Lee I. Chiba, Henry W. Ivey, Keith A. Cummins, and Brian
E. Gamble
Background Information & Objectives The competition between humans and pigs for quality sources of
protein is likely to increase continuously because of the ever-increasing
world population. The effort to find viable alternative protein
sources for pigs is, therefore, important for successful swine
production in the future. Hydrolyzed feather meal (FM) has been
of interest in nutrition research because of its high protein
content, but it is deficient in some amino acids, especially
lysine. Because the adequacy of lysine is the primary concern
for most swine diets, it is generally recommended that the use
of FM should be limited to about 5% of the diet for optimum performance.
However, previous research indicated that finisher pigs may be
able to utilize higher levels of FM than those commonly recommended.
The research described herein was conducted to evaluate the value
of FM as a source of dietary amino acids for finisher pigs, and
to determine the possibility of replacing soybean meal (SBM)
completely with FM by lysine supplementation.
Experimental Procedures, Results & Conclusions
To determine the optimum level of dietary
FM, five iso-lysinic (7.3 g/kg) SBM diets were formulated to
contain 0, 30, 60, 90 or 120 g FM/kg. Two additional diets containing
90 g FM kg-1 were used to investigate the possibility of replacing
SBM completely with FM. The FM diets were formulated to be iso-nitrogenous
to the SBM diet containing 0 g FM/kg, and L-lysineùHCl was
added to one of the two diets to achieve 7.3 g lysine/kg. All
indispensable amino acid contents of this diet were at least
20.8% greater than the current NRC recommendations. To avoid
possible confounding effects of dietary energy density, dried
fat product was used to achieve similar energy contents of all
diets (3.45 Mcal DE/kg). At an average weight of 67.5 +/- 3.4
kg, 21 gilts and 21 castrated males were randomly assigned within
sex to seven dietary treatments. Pigs were housed individually,
and allowed ad libitum access to feed and water. All pigs were
slaughtered at an average weight of 100.4 +/- 3.2 kg to assess
carcass traits. The rate (linear, P < .05; cubic, P = .09) and
efficiency of weight gain (linear, P = .07) decreased as dietary
FM increased. However, the response of pigs to the initial increment
of FM (30 g/kg) in weight gain and greater feed intake of pigs
fed the diet containing 120 g FM kg-1 seemed to be responsible
for overall decreases in these criteria. The rate and efficiency
of weight gain in pigs fed other SBM diets containing FM were
similar. Although there were no statistically significant trends
among pigs fed the SBM diets, the inclusion of 120 g FM/kg seemed
to result in the inferior carcass quality as indicated by consistently
lower values for carcass specific gravity (1.040 vs 1.045), proportion
of carcass lean (48.7 vs 51.6%) and the rate of lean accretion
(236.4 vs 301.4 g d-1). Pigs fed the two FM diets (with and without
lysine supplementation) grew slower than those fed the SBM diet
containing 0 (P < .01) or 90 g FM/kg (P = .06). Similar results
were obtained for the efficiency of weight gain (P < .05) and
rate and efficiency of lean accretion (P < .05). There was no
effect of lysine supplementation on the rate and efficiency of
weight gain. Pigs fed the FM diet supplemented with lysine, however,
had less 10th rib backfat (P = .10), larger longissimus muscle
area (P = .08), greater proportion of carcass lean (P < .05),
and higher rate (P = .08) and efficiency of lean accretion (P < .05)
than those fed the FM diet without lysine supplementation. The results indicate that FM up to 90 g/kg may be incorporated in the diet
without adversely affecting carcass traits of finisher pigs. In addition, although
weight gain may be reduced, FM can be used as the only source of protein supplement
without decreasing the carcass quality, provided that the diet is supplemented
with crystalline lysine to alleviate its deficiency.
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