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The Effect of Environmental Flock Treatments on Broiler Carcass Quality1
1476
RESEARCH NOTES
THE EFFECT OF ENVIRONMENTAL FLOCK TREATMENTS ON BROILER CARCASS QUALITY1 PAUL DEAN, HEATHER SUTTON AND F. G. PROUDFOOT Research Station, Canada Department of Agriculture, KentviUe, Nova Scotia (Received for publication March 9, 1972)
POULTRY SCIENCE 51: 1476-1477,
The effect on carcass quality of a number of growing treatments were evaluated. This investigation estimated the interrelated effects of differential floor, waterer and feeder space treatments during the growing period of one commercial broiler genotype. Measurements on cooking loss, moisture content, fat extract, texture and color were determined. The environmental conditions consisted of two intermittent light treatments made up of light and dark cycles of (1) 1 hour light and 3 hours darkness, and ( 2 ) 3 hours light and 1 hour darkness. Within each light treatment 3 pen population densities were housed, they were 40, 100 and 160 birds per pen (15.8 m.2) in a total of 24 pens with 8 pens allotted to each population density. One-half of the pens were equipped with 2 waterers and the remaining pens provided with 1 waterer. Two feeder space treatments were also evaluated. The two feeder space treatments consisted of 4 feeders per pen versus 1 feeder per 20 birds housed. Five birds from each of the 3 pen population densities were se1
Contribution No. 14S0.
1972
lected for a paired-comparison difference texture panel (Larmond, 1970). For the objective measurements 4 male birds were randomly selected from each pen making a total of 96 birds. Birds were slaughtered and processed at 8 weeks of age in a commercial processing plant, chilled over night in ice and frozen the following day. The broilers were then thawed overnight as required. They were cooked at a temperature of 167°C. for a time calculated according to their body weight (twelve grams of body weight were equivalent to one minute of cooking time). They were wrapped with aluminum foil before cooking and drained after cooking for a one-hour period. Five objective measurements were carried out on the broilers. Cooking loss, color, moisture and fat extract were determined as described by Dean et al. (1971). The texture measurements were taken on the pectoralis secundus breast muscle. A 1 cm.2 strip 6.S cm. long was placed in a Kramer shear cell. This was repeated twice and the peak of the curve taken as the force needed to shear the sample. Results from the sensory taste panel re-
Downloaded from http://ps.oxfordjournals.org/ at University of Hawaii, PBRC, Kewalo Marine Lab. on June 6, 2015
ABSTRACT The effect on carcass quality of differential floor, waterer and feeder space treatments was estimated. Measurements on tenderness, cooking loss, moisture content, fat content, texture and color were determined. Results from a sensory taste panel revealed a statistically significant difference in toughness between birds grown in low and high density environments; birds grown under high density conditions exhibited more carcass tenderness. The results of the texture measurements provided supporting evidence as the muscle shearing force requirements were higher for birds from the low density pens; this difference approached significance at the 5% level. Moisture content, color, fat extract and cooking loss were unaffected by the rearing treatments except for feeder space by waterer space interaction for moisture content, and a feeder space effect on meat color which requires further research for substantiation of these results.
RESEARCH NOTES TABLE 1.—Results of sensory panel on texture of the pectoralis secundus Number of birds
Percent evaluation for texture
confared
40 tou
Sher
No
40 vs. 100
50 20 30 40 tougher No difference 160 tougher
difference 100 tougher
58**
27
15
** Significant at the 1% level.
vealed a statistically significant difference in toughness between a bird density of 40 birds per pen and 160 birds per pen. Birds from 40 bird pens exhibited a higher degree
TABLE 2.—The effect of bird density on carcass traits Bird Moisture Texture Density % kg. 40 100 160
68.4 69.2 68.7
42.2 36.0 36.8
Color index 73.8 74.1 74.0
Fat e
*£ a c t
Cooking >°ss
1.5 1.4 1.5
29.7 27.4 28.0
waterer space interaction indicates that as feeder and waterer space was increased carcass moisture content declined (Table 3). Feeder space also had a significant effect on the color of the carcass flesh. Percent fat extract and cooking loss were unaffected by feeder space, waterer space or bird density.
TABLE 3.—Mean squares of analysis of variance of moisture texture, color, fat extract and cooking loss Carcass traits Source of variance
df.
1 Light treatment 1 Feeder/zone 2 Waterer/zone 2 Bird density/zone 4 Feeder X waterer/zone 2 FeederX density/zone 4 WatererX density/zone 4 Feeder X waterer X density /zone 4 Error 72
Moisture
Texture
Color
Fat extract
Cooking loss
5.1894 0.1544 1.8931 1.5164 2.9458* 0.9473 1.6304 0.7333 0.7198
149.75 120.39 92.67 210.96 129.63 41.88 236.25 107.25 97.81
4.2294 4.9551* 1.6910 0.8452 0.5931 1.0225 1.6549 0.4267 1.4696
0.9146 0.0240 1.1931 1.4518 0.4590 1.4317 2.1431 0.3727 0.9563
18.851 10.613 14.399 13.835 12.710 14.294 3.935 5.844 6.946
:
No appropriate test was available to estimate differences between light treatments. " Significant at the 5% level.
of toughness than birds from pens containing 160 birds (Table 1). Bird density of 40 birds per pen resulted in a higher shear cell reading (42.2 kg.) compared with 36.0 and 36.8 kg. for birds from pens with 100 and 160 birds respectively (Table 2). This shear cell difference approached significance at the five percent level demonstrating that as bird density increases the texture becomes more tender. The meat tenderness found in birds from pens with high population density may be associated with the restriction in exercise associated with reduced floor space per bird. The statistically significant feeder X
ACKNOWLEDGEMENT
The authors express appreciation to Dr. D. T. Spurr, Statistical Research Service, Canada Department of Agriculture, Ottawa, for advice and assistance in the statistical analyses of the data. REFERENCES Dean, P., F. G. Proudfoot, E. Larmond and J. R. Aitken, 1971. The effect of feeding diets containing white fishmeal on acceptability and flavor intensity of roasted broiler chickens. Can. J. Anim. Sci. SI: 15-20. Larmond, E., 1970. Methods for sensory evaluation of food. Can. Dept. Agr. Publ. 1284. Ottawa, Ont.
Downloaded from http://ps.oxfordjournals.org/ at University of Hawaii, PBRC, Kewalo Marine Lab. on June 6, 2015
40 vs. 160
1477
RESEARCH NOTES
THE EFFECT OF ENVIRONMENTAL FLOCK TREATMENTS ON BROILER CARCASS QUALITY1 PAUL DEAN, HEATHER SUTTON AND F. G. PROUDFOOT Research Station, Canada Department of Agriculture, KentviUe, Nova Scotia (Received for publication March 9, 1972)
POULTRY SCIENCE 51: 1476-1477,
The effect on carcass quality of a number of growing treatments were evaluated. This investigation estimated the interrelated effects of differential floor, waterer and feeder space treatments during the growing period of one commercial broiler genotype. Measurements on cooking loss, moisture content, fat extract, texture and color were determined. The environmental conditions consisted of two intermittent light treatments made up of light and dark cycles of (1) 1 hour light and 3 hours darkness, and ( 2 ) 3 hours light and 1 hour darkness. Within each light treatment 3 pen population densities were housed, they were 40, 100 and 160 birds per pen (15.8 m.2) in a total of 24 pens with 8 pens allotted to each population density. One-half of the pens were equipped with 2 waterers and the remaining pens provided with 1 waterer. Two feeder space treatments were also evaluated. The two feeder space treatments consisted of 4 feeders per pen versus 1 feeder per 20 birds housed. Five birds from each of the 3 pen population densities were se1
Contribution No. 14S0.
1972
lected for a paired-comparison difference texture panel (Larmond, 1970). For the objective measurements 4 male birds were randomly selected from each pen making a total of 96 birds. Birds were slaughtered and processed at 8 weeks of age in a commercial processing plant, chilled over night in ice and frozen the following day. The broilers were then thawed overnight as required. They were cooked at a temperature of 167°C. for a time calculated according to their body weight (twelve grams of body weight were equivalent to one minute of cooking time). They were wrapped with aluminum foil before cooking and drained after cooking for a one-hour period. Five objective measurements were carried out on the broilers. Cooking loss, color, moisture and fat extract were determined as described by Dean et al. (1971). The texture measurements were taken on the pectoralis secundus breast muscle. A 1 cm.2 strip 6.S cm. long was placed in a Kramer shear cell. This was repeated twice and the peak of the curve taken as the force needed to shear the sample. Results from the sensory taste panel re-
Downloaded from http://ps.oxfordjournals.org/ at University of Hawaii, PBRC, Kewalo Marine Lab. on June 6, 2015
ABSTRACT The effect on carcass quality of differential floor, waterer and feeder space treatments was estimated. Measurements on tenderness, cooking loss, moisture content, fat content, texture and color were determined. Results from a sensory taste panel revealed a statistically significant difference in toughness between birds grown in low and high density environments; birds grown under high density conditions exhibited more carcass tenderness. The results of the texture measurements provided supporting evidence as the muscle shearing force requirements were higher for birds from the low density pens; this difference approached significance at the 5% level. Moisture content, color, fat extract and cooking loss were unaffected by the rearing treatments except for feeder space by waterer space interaction for moisture content, and a feeder space effect on meat color which requires further research for substantiation of these results.
RESEARCH NOTES TABLE 1.—Results of sensory panel on texture of the pectoralis secundus Number of birds
Percent evaluation for texture
confared
40 tou
Sher
No
40 vs. 100
50 20 30 40 tougher No difference 160 tougher
difference 100 tougher
58**
27
15
** Significant at the 1% level.
vealed a statistically significant difference in toughness between a bird density of 40 birds per pen and 160 birds per pen. Birds from 40 bird pens exhibited a higher degree
TABLE 2.—The effect of bird density on carcass traits Bird Moisture Texture Density % kg. 40 100 160
68.4 69.2 68.7
42.2 36.0 36.8
Color index 73.8 74.1 74.0
Fat e
*£ a c t
Cooking >°ss
1.5 1.4 1.5
29.7 27.4 28.0
waterer space interaction indicates that as feeder and waterer space was increased carcass moisture content declined (Table 3). Feeder space also had a significant effect on the color of the carcass flesh. Percent fat extract and cooking loss were unaffected by feeder space, waterer space or bird density.
TABLE 3.—Mean squares of analysis of variance of moisture texture, color, fat extract and cooking loss Carcass traits Source of variance
df.
1 Light treatment 1 Feeder/zone 2 Waterer/zone 2 Bird density/zone 4 Feeder X waterer/zone 2 FeederX density/zone 4 WatererX density/zone 4 Feeder X waterer X density /zone 4 Error 72
Moisture
Texture
Color
Fat extract
Cooking loss
5.1894 0.1544 1.8931 1.5164 2.9458* 0.9473 1.6304 0.7333 0.7198
149.75 120.39 92.67 210.96 129.63 41.88 236.25 107.25 97.81
4.2294 4.9551* 1.6910 0.8452 0.5931 1.0225 1.6549 0.4267 1.4696
0.9146 0.0240 1.1931 1.4518 0.4590 1.4317 2.1431 0.3727 0.9563
18.851 10.613 14.399 13.835 12.710 14.294 3.935 5.844 6.946
:
No appropriate test was available to estimate differences between light treatments. " Significant at the 5% level.
of toughness than birds from pens containing 160 birds (Table 1). Bird density of 40 birds per pen resulted in a higher shear cell reading (42.2 kg.) compared with 36.0 and 36.8 kg. for birds from pens with 100 and 160 birds respectively (Table 2). This shear cell difference approached significance at the five percent level demonstrating that as bird density increases the texture becomes more tender. The meat tenderness found in birds from pens with high population density may be associated with the restriction in exercise associated with reduced floor space per bird. The statistically significant feeder X
ACKNOWLEDGEMENT
The authors express appreciation to Dr. D. T. Spurr, Statistical Research Service, Canada Department of Agriculture, Ottawa, for advice and assistance in the statistical analyses of the data. REFERENCES Dean, P., F. G. Proudfoot, E. Larmond and J. R. Aitken, 1971. The effect of feeding diets containing white fishmeal on acceptability and flavor intensity of roasted broiler chickens. Can. J. Anim. Sci. SI: 15-20. Larmond, E., 1970. Methods for sensory evaluation of food. Can. Dept. Agr. Publ. 1284. Ottawa, Ont.
Downloaded from http://ps.oxfordjournals.org/ at University of Hawaii, PBRC, Kewalo Marine Lab. on June 6, 2015
40 vs. 160
1477