蛋白質源としてのメタノール資化細菌が鶏の育成•産卵成績•繁殖能力および臓器重量におよぼす影響

In a collaborative study by research institutions at three prefectures methanol-utilizing bacteria (SCP), was investigated for its influence on the growth of chickens, egg production, reproduction, organ weight and incidence of fatalities, and the level of heavy metals in poultry farm produces. This experimental study took a period of five years and a half from September, 1975 through January, 1981.<br>Three feeding trials were conducted using (1) a continuous feeding experiment where birds were kept to 212 weeks of age over about four years (lifetime birds), (2) a long-term multiple generation experiment when chicks were obtained at 68 weeks from the hatching test of the lifetime birds and at a similar stage from two subsequent generations and (3) a short-term multiple generation test which was based on six generations each lasting 36 weeks.<br>For all birds and in each group, chicks were continuously fed either the control feed or the SCP feed (11.7%) from the day of hatching onwards. The test provided growth and laying performance data for a total of 3, 039 birds, hatchability data for a total of 34, 432 fertile eggs, mortality incidence, organ weights of the liver, kidneys, heart, spleen, gizzard, glandular stomach and thyroid derived from 200 birds obtained from 10 birds per group selected at random at the end of each test term of each generation, and the total Hg, Pb, Cd, As₂O₃ and 3, 4-benzopyrene levels in the test feeds and in the eggs, femoral muscles and livers at the age of 212 weeks.<br>(1) Results at the growing period<br>There were no differences regarding viability and the age of 50% egg production between groups in any feeding trial. Body weight consistently tended to be less for SCP groups. Egg weight at 50% egg production, feed intake and feed conversion varied between generations but showed no significant differences.<br>(2) Results in laying periods<br>SCP groups showed slightly higher egg output in all feeding trials but differences were not significant. Feed intake and feed conversion were the same for both diets in all feeding trials. Average egg weight tended to be less for both long-term and short-term multigeneration birds in the SCP groups. Feeding with SCP had no influence on body weight, survival rate or mortality.<br>(3) Results of hatchability tests<br>SCP had no influence on fertility, hatchability-to-fertile, and dead-in-shell rate.<br>(4) Organ weights<br>There was no difference between SCP and control groups.<br>(5) Levels of toxic metals and contaminants in animal tissues<br>Hg, Pb, Cd, As₂O₃ and 3, 4-benzopyrene were not detected in eggs and femoral muscles. Hg and Cd were detected in the liver but there was no difference between SCP and control groups. The levels of these substances were lower in the test diet compared to control.