Institut für Ernährungswissenschaften (Institute of Nutritional Sciences), Technische Universität München, Hochfeldweg 6, 85350 Freising, Germany
E-mail: Roth-Maier@weihenstephan.de
Abstract
The feeding of full-fat canola seed to poultry was tested in a fattening trial with broiler chicks and in a feeding experiment with laying hens (white light laying hybrids, LSL). Canola seed was included in proportions of 0, 5, 10, 15, 20 and 25% of the compound feeds as a replacement for soybean meal. Performance data of broilers and layers, the profile of the egg fatty acids and also the sensory quality of the eggs were tested. In both cases already the lowest proportions of 5 and 10%, respectively, reduced the performance data significantly. Sensory traits of the eggs, were not affected by feeding of 25% canola seed, the proportions of oleic and linoleic acid in the eggs were highest and reflected the changes in the fatty acid contents of the diets.
The influence of dietary levels of canola meal in amounts of 0, 10, 15, 20, 25 and 30% to broilers and 0, 6.7, 10, 13.3, 16.7 and 20% to layers was proved in another series of experiments. Performance data of broilers and laying hens, sensory traits of meat and eggs and weights of the thyroid glands of the broilers were determined. The results indicated that canola meal can be given to broilers and hens (only layers that produce white-shelled eggs) in proportions up to 15 % in compound feeds.
KEYWORDS: Fattening chickens, laying hens, performance, yolk fatty acids, sensory traits
Introduction
Canola seed is used in animal nutrition either as full fat seed or as the protein-rich residue canola meal. Both components are different in their composition and require therefore also different feeding strategies. The effective use of these feedstuffs in poultry feeding was the aim of the investigations presented in this paper.
FULL-FAT CANOLA SEED TO BROILER CHICKENS AND LAYING HENS
The experiment with broiler chickens was conducted over 6 weeks using 360 day-old male fattening hybrids (Ross). The animals were divided in 6 groups. Full fat canola seed was included in proportions of 0, 5, 10, 15, 20 and 25 % of the compound feeds as a replacement for soybean meal. The locally grown canola seed contained 22.1% crude protein, 43.1% crude fat in dry matter (DM) and 15.4 µmol glucosinolates / g seed. The diets were based on wheat and were optimally supplemented with minerals and vitamins. They contained 29% crude protein and 14.7 MJ MEN-corr. in DM. They were isoenergetic and isonitrogeneous and adequate in all essential amino acids (for more details see Roth-Maier and Kirchgeßner, 1995). The criteria measured were the growth development, feed intake and feed conversion.
Selected results of the experiment are summarised in table 1. These data show that increasing proportions of canola seed in the diet reduce continuously performance. The depressing effects of the seed occurred already after the first week and continued during the whole fattening period.
Table 1: Full-fat canola seed to fattening chickens
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Laying hens (light white laying hybrids, 5x12 hens per group) were kept individually and were fed also isonitrogenous and isoenergetic diets with 0, 10, 15, 20 and 25% canola seed in the diet on a wheat, barley and soybean meal basis. The diets contained 17% crude protein and 12.5MJ ME N-corr. in DM. The parameters were live weight, egg production, daily egg mass, odour and flavour of the eggs, the fat content and the fatty acid proportions of the egg yolk (Roth-Maier and Kirchgeßner, 1995).
The performance data (table 2) show that already 10% canola seed in the diet reduced performance, which was obvious in the distribution of the egg sizes. In the soybean meal group (control group)
Table 2: Full-fat canola seed to laying hens
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Egg weight, g |
71.6 |
a |
69.0 |
ab |
67.3 |
b |
65.6 |
b |
66.2 |
b |
Egg production, % |
83 |
80 |
81 |
79 |
82 |
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Daily egg mass, g |
59.1 |
54.8 |
54.3 |
51.6 |
54.0 |
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Yolk fat, % |
29.2 |
29.2 |
30.1 |
29.7 |
29.9 |
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Yolk fatty acids, g of 100g total fatty acids |
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C18 : 0 |
9.8 |
a |
9.0 |
b |
8.4 |
c |
7.4 |
d |
7.2 |
d |
C18 : 1 |
36.4 |
c |
41.9 |
d |
45.1 |
c |
47.9 |
b |
50.9 |
a |
C18 : 2 n-6 |
24.4 |
a |
20.5 |
b |
18.3 |
c |
17.2 |
d |
14.8 |
e |
C18 : 3 n-3 |
2.5 |
c |
2.7 |
bc |
2.9 |
ab |
3.0 |
a |
3.0 |
a |
C20 : 4 n-6 |
1.7 |
a |
1.6 |
b |
1.5 |
b |
1.5 |
b |
1.4 |
c |
C22 : 6 n-3 |
1.4 |
ab |
1.4 |
ab |
1.4 |
ab |
1.3 |
b |
1.5 |
a |
55% of the egg weights were in the range of >75 - 70g. With 10% canola seed only 32 % of the eggs reached this size and this effect continued in response to increasing canola seed amounts. With respect to the sensory quality no difference occurred between the groups. The proportions of the unsaturated and essential fatty acids in the eggs reflected the amount of intake and the composition of the canola oil. Increasing canola proportions resulted in increasing oleic acid proportions, reduced linoleic and arachidonic acid proportions and significantly higher proportions of linolenic acid in the yolk.
Based on these experiments it is concluded that even low amounts of full fat canola seed in the diets have detrimental effects on performance of poultry and use in feeding can not be recommended. These effects may be explained by the contents of intact glucosinolates and also their degradation products, which may induce more metabolic disturbances than the degradation products of the residue canola meal.
CANOLA MEAL TO BROILER CHICKENS AND LAYING HENS
The influence of feeding the protein feedstuff canola meal to broilers was tested in a fattening trial of 5 weeks (Roth-Maier and Kirchgeßner, 1987). Six groups of 90 animals, each, were given 0, 10, 15, 15, 20, 25 and 30% canola meal as a replacement of soybean meal in isonitrogenous and isoenergetic diets based on wheat, corn, animal fat blend, fish meal, corn gluten and soybean meal. The parameters measured were the performance, the sensory traits of the meat and the weights of the thyroid glands.
Table 3: Canola meal to fattening chickens
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Daily feed intake, g |
68.6 |
a |
68.3 |
a |
65.9 |
ab |
63.7 |
b |
63.5 |
b |
60.5 |
c |
Feed conversion, kg feed / |
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Thyroid gland mg / kg |
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The results indicate, that proportions up to 15% canola meal can be used in diets for fattening chickens, because feed conversion was still similar as in the control group, although weight gains and feed intake were reduced by 4%. The sensory quality of the meat remained unchanged even when 30% canola was given.
Similar recommendations for practical diets including canola meal can be given for laying hens. This was tested in an one year experiment starting at the beginning of the laying period of the hens (25 weeks old). 72 light white laying hybrids (LSL) were kept individually and divided in 6 groups with 0, 6.7, 10, 13.3, 16.7, and 20% canola meal (Roth-Maier and Kirchgeßner, 1988).
Table 4: Canola meal to laying hens
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Daily feed intake, g |
110 |
a |
105 |
ab |
108 |
ab |
107 |
ab |
106 |
ab |
101 |
b |
Egg production, % |
86 |
87 |
89 |
89 |
89 |
89 |
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Egg weight, g |
61.5 |
61.8 |
61.2 |
61.3 |
61.6 |
59.9 |
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Egg mass, g |
53.1 |
53.9 |
54.4 |
54.3 |
55.0 |
53.2 |
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Feed per kg egg mass, kg |
2.08 |
1.94 |
1.99 |
1.98 |
1.97 |
1.92 |
Table 4 shows selected results of this experiment. 20% Canola meal reduced feed intake significantly. The other parameters were not influenced by the various canola meal proportions. However, the distribution of the egg weight classes was influenced in such a way, that in response to the higher canola meal proportions the production of lower-sized eggs increased. In the control group 34% of the eggs were in the range up to 60 g and 28% had egg weights >65 g. However, in the 20% canola meal group 53 % of the eggs were in the range up to 60 g egg weight and only 15% of the eggs weighed >65 g. Odour and flavour of the eggs were not influenced by feeding canola meal.
From these results it is concluded that canola meal can be used up to 15% of the diet for broilers and white laying hens. This recommendation, however, is valid only for laying hens, that produce white-shelled eggs, because in brown layers the risk of tainted eggs cannot be excluded.
References
1. Roth-Maier, Dora A. and M. Kirchgeßner, 1987: Zum Einsatz von Rapsextraktionsschrot aus 00-Sorten in der Broilermast. Arch. Geflügelk. 51, 241-246.
2. Roth-Maier, Dora A. and M. Kirchgeßner, 1988: Zum langfristigen Einsatz von Rapsextraktionsschrot aus 00-Sorten an Legehennen. Landwirtschaftl. Forschung, 41, 140-150.
3. Roth-Maier, Dora A. and M. Kirchgeßner, 1995: Untersuchungen zum Einsatz von 00-Rapssaat in der Geflügelfütterung. Arch. Geflügelk. 59, 241-246.
