Growth and digestive function of turkeys surviving the poult enteritis and mortality syndrome

Stunted growth of poults afflicted by enteritis mortality syndrome (PEMS) may be associated with depressed digestive capabilities. We conducted two experiments to test this hypothesis. Survivors of PEMS were obtained from a research flock that had been purposefully infected at 5 d of age with PEMS inoculum that included turkey corona virus. The PEMS survivors were assigned to Experiments 1 and 2, beginning at 40 and 35 d of age, respectively. Three groups (large, L; medium, M; and small, S) and two groups (L and S) of 20 poults each were selected to represent different degrees of stunting in Experiments 1 and 2, respectively. When the body weights of each group in both experiments were plotted using initial body weight as the starting point, all of the weights fell on the normal growth curve except Group S in Experiment 1. Therefore, there was no evidence of compensatory growth over the period studied. In Experiment 1, apparent fat absorption (AFA) was significantly higher (P < 0.05) for control (85.9%) than for M (78.5%) and S (78.3%) groups, and AME, for the control group was significantly higher than all the PEMS-survivor groups. In Experiment 2, Group L had a higher AFA and AMEn than Group S. AFA and AMEn improved in both groups over time. The digestive capabilities of PEMS survivors were depressed proportionally to the degree of stunting. Impaired fat digestibility and dietary energy utilization in PEMS-afflicted birds are likely contributors to stunted growth and reduced recovery rates.

Effects of amino acid restriction during starter and grower periods on subsequent performance and incidence of leg disorders in two strains of male large white turkeys

Male turkeys of two commercial Large White strains (Nicholas 88, BUT 6) were subjected to growth restriction by means of reducing amino acid (AA) content of diets to a minimum of 75% of NRC (1994) suggested levels. There were three periods when diets containing 75% of NRC recommended AA for that age period were fed ad libitum: 0 to 3 wk, 0 to 6 wk, or 6 to 12 wk. A fourth (control) group was not restricted in AA content at any time. When turkeys were not fed the AA-restricted diets they were fed diets formulated to meet a minimum of 100, 110, or 120% of NRC (1994) AA recommendations, which resulted in a 3 x 4 factorial arrangement of treatments with three AA levels by four restriction times. Four pens of 12 males each were fed each AA by restriction time combination. At 18 wk, all birds were scored individually for leg condition and representative samples of turkeys were processed for parts yield. Birds fed restricted diets from 0 to 6 or 6 to 12 wk had significantly lower BW at 18 wk than control birds. Birds fed the restricted diets from 0 to 3 wk did not differ significantly in 18-wk BW compared to control birds but the magnitude of difference was similar to that observed at the end of the restriction period. Feed utilization was not improved by early AA restriction. Restricting early growth resulted in a significantly higher incidence of birds with no leg disorders and a lower incidence of birds with moderate leg disorders than control birds. Feeding higher AA levels during realimentation resulted in a greater severity of leg disorders. Breast meat yield was depressed significantly as severity of early restriction increased. Increasing dietary AA above NRC (1994) recommended levels generally improved performance during realimentation but was not able to compensate for reduced gains during restriction.

Effects of amino acid restriction during starter and grower periods on subsequent performance and incidence of leg disorders in male large white turkeys

Male Nicholas Large White turkeys were fed diets formulated to meet a minimum of 100, 110, or 120% of NRC (1984) amino acid recommendations. There were three periods when 75% of recommended standards were fed: 0 to 3 wk, 0 to 6 wk, or 6 to 12 wk. A fourth (control) group was not restricted at any time. Four pens of 12 males were fed each amino acid by restriction combination. At 18 wk, leg scores were assigned to all birds and representative samples of birds processed for parts yield. All birds fed restricted diets had significantly lower BW at 18 wk than unrestricted controls but did not differ in feed utilization. Dietary amino acid levels significantly influenced BW and feed utilization, but there was no interaction with restriction times. There were no significant effects of amino acid levels or restriction times on incidence of leg disorders. Breast meat yields (quantity and percentage of carcass) were significantly influenced by both restriction time and amino acid levels. There seemed to be little if any compensatory gain following amino acid restriction in these studies.