In order to evaluate the effects of cassava leaf meal (CLM ) and field crab roe (FCR) as supplements in commercial concentrate diets on yolk colour of quail eggs, a trial was carried out in a small farm in Cantho City for four months. The design was a completely randomized design with two hundred and forty female quails at an age of twenty-one days allocated to four different diets and three replicates. The treatments were: a commercial concentrate (CC); CC with 5% CLM (CLM5); CC with 3% CLM and 2% FCR (CLM3FCR2); and CC with 5% FCR (FCR5).
The degree of yellowness of yolks on the diet supplemented with 5% CLM and with 5% FCR was higher than for the control diet. The eggs from birds in the treatment with 5% FCR had darker and more chromatic yellow yolks than in the control treatment. The yolks of the quails supplemented with 5% FCR were heavier than on the other treatments. The ratio between the weight of yolk and white was significantly higher in the diet with 5% field crab roe than the control diet . Mean weight of quail eggs given the diet with 5% field crab roe was significantly higher than for the other treatments as was laying rate and feed conversion.
Although there have been many studies carried out on the use of cassava products for livestock, no information is available on the effect of including them in diets for quails. The crude protein of cassava leaves can be as high as 350 g/kg of DM. Under tropical conditions, cassava leaves proved to be useful in diets for growing pigs to improve the dietary protein supply (Bui Huy Nhu Phuc et al 2001).
Carotene levels in cassava leaves are high, with some samples from south Vietnam containing up to 1000 ppm (Duong Thanh Liem 1989). Including up to 6% cassava leaf meal in diets for Leghorn hens has been shown to be possible without any symptoms of poisoning (Duong Thanh Liem 1997). Results of a trial on the replacement of maize in the diet by ground cassava root and 6 % green material from Trichanthera gigantea showed that the yolks of quails fed this diet had the same colour as for the maize control diet (Phong Van My 1994).
Field crabs produce large amounts of roe between August and November,
particularly in Dong Thap, Long Xuyen, An Giang and Tay Ninh Provinces. The
crabs are collected, and after their chelae have been removed ,the remains are
thrown away, causing local pollution. However, between 100 to 200g of roe can be
extracted from 100 crabs, although this is time consuming. The objective of
this experiment was to determine the effect of cassava leaf meal and field crab
roe as feed supplements on the colour of the yolks in Quail eggs.
The study was conducted with two hundred and forty quails at 21 days of age and lasted until the end of the fifth week of lay. The quails were allocated in a completely randomized design with four treatments and three replications. The dietary treatments were:
CC: Control (commercial concentrate)
CLM5: CC + 5% cassava leaf meal
CLM3FCR2: CC + 3% CLM + 2% field crab roe (FCR)
FCR5: CC + 5% FCR
The nutrient composition of the commercial concentrate used was as follows: crude protein 31% and crude fibre <6%. The control diet consisted of the concentrate (Proconco Mill Company) mixed with maize and rice brain the following proportions: (%, as fed): maize meal 45, rice bran 10, concentrate 45.
Cassava leaves were collected in Chau Thanh district in Can Tho province. The clean, fresh, green cassava leaves were sun-dried for two or three days and were then ground to a meal with a particle size less than 1 mm and stored in nylon bags before mixing with the control diet. Sun-dried cassava leaf meal contains 93.2 % DM, 19.5 % crude protein and 589 ppm carotene according to Duong Thanh Liem (1993).
Crabs shells were separated from their abdomens and cleaned with fresh water before the roe was removed and steamed for a short time.
Colour of yolk was measured by a colorimeter, and included three parameters: lightness or darkness of yolk (L); chromaticity coordinates (a and b), where a is redness, -a is greenness, +b is yellowness, and -b is blueness. The weights of white, yolk, and eggs were measured after collecting three eggs from each dietary treatment / replicate. The yolks of the quail eggs were analysed for dry matter, crude protein, ether extract, calcium and phosphorus. Egg production and feed consumption were recorded per week from the sixth to fifteenth week of lay.
|
Table 1. Nutrient composition of the experimental diets (% on DM basis, except for DM which is on air-dry basis) |
||||
|
|
CC |
CLM5 |
CLM3 FCR2 |
FCR5 |
|
DM |
91.1 |
90.6 |
89.7 |
90.4 |
|
CP |
22.4 |
21.8 |
23.9 |
23.4 |
|
EE |
3.96 |
4.36 |
5.31 |
4.16 |
|
Ash |
14.9 |
16.3 |
15.5 |
15.2 |
|
CF |
5.13 |
5.48 |
5.18 |
5.31 |
|
ADF |
6.05 |
6.44 |
6.71 |
6.35 |
|
NDF |
14.4 |
14.3 |
13.9 |
14.0 |
|
Ca |
4.57 |
5.20 |
4.77 |
5.13 |
|
P |
0.60 |
0.55 |
0.59 |
0.60 |
Data were analysed by ANOVA using the General Linear Model and Tukey Test
Comparisons of the Minitab Statistical Software version 12. The sources of
variation were: treatments and error.
The quails fed the diets containing cassava leaf meal and / or field crab roe, had yolks with lower values for lightness compared witht he control (CC) (Table 2). Greenness, coming close to red, and chromatic value were higher for the yolk of eggs from the quails fed CLM than for the others. The yolks of eggs from quail fed field crab roe alone (FCR%) diet did not differ from the control.
|
Table 2. Effect of diet on yolk colour (Means and SE) |
||||||
|
|
CC |
CLM5 |
CLM3FCR2 |
FCR5 |
Prob |
SEM |
|
Lightness "L" |
52.3b ± 0.18 |
51.3a ± 0.18 |
51.6ab ± 0.18 |
51.8ab±0.17 |
0.001 |
0.25 |
|
Greenness "-a" |
-1.45b ± 0.13 |
-0.73a ± 0.13 |
-0.87a ± 0.13 |
-1.48b± 0.13 |
0.001 |
0.19 |
|
Yellowness "b" |
37.1 b ± 0.31 |
39.7a ±.0.31 |
38.7a ± 0.31 |
37.2b±0.31 |
0.001 |
0.44 |
|
ab Means in the same row without letter in common are different at P<0.05 |
||||||
Eggs from quail fed the 5% field crab roe diet (Table 3) had the heaviest yolks and the highest proportion of yolk. The product of reproduction of the crab is the roe that contains lipid, protein, lipo-protein and vitellin, which can be converted into the nutrients of yolk by laying quails. This explains why the quails supplied with 5% field crab roe laid eggs having higher ratios between yolk and white and heavier yolk weight than the quails given the other diets.
|
Table 3. Effect of diet on yolk weight and the ratio between yolk and white weight |
||||||
|
|
CC |
CLM5 |
CLM3FCR2 |
FCR5 |
Prob. |
SEM |
|
White weight, g |
5.62a ± .051 |
5.72a ± .051 |
5.54a ± .051 |
5.64a ± .050 |
0.1 |
7.1 |
|
Yolk weight, g |
3.35b ± .033 |
3.36b ± .033 |
3.31b ± .033 |
3.48a ± .032 |
0.002 |
6.2 |
|
Yolk, % of yolk+white |
59.9b ± .006 |
59.2b ± .006 |
59.9ab ± .006 |
62.0a± .006 |
0.002 |
0.8 |
|
ab Means in the same row without letter in common are different at P<0.05 |
||||||
Cassava leaves have more carotene and other pigments that are incorporated into the yolk, which might explain why yolks of the quails fed 5% cassava leaf meal appeared to have the highest dry matter content (Table 4).
|
Table 4. Effect of dietary supplements on the nutrient composition of yolk (% ) |
||||
|
|
CC |
CLM5 |
CLM3FCR2 |
FCR5 |
DM |
51.5 |
56.5 |
48.3 |
51.7 |
|
CP |
30.9 |
29.0 |
31.9 |
29.3 |
|
EE |
62.3 |
59.2 |
60.7 |
64.1 |
|
Ca |
0.39 |
0.34 |
0.46 |
0.39 |
|
P |
0.86 |
0.71 |
0.99 |
0.91 |
Eggs from quails fed 5% field crab roe tended to be heavier and laying rate and feed conversion were better than on the other diets (Table 5). It is probable that the rich array of nutrients in the field crab roe was responsible for these effects.
|
Table 5. Effect of diet on egg weight and rate of production |
||||||
|
|
CC |
CLM5 |
CLM3FCR2 |
FCR5 |
Prob. |
SEM |
|
Mean egg weight, g |
10.6b ± 0.04 |
10.8ab± 0.04 |
10.7b ± 0.04 |
10.9a ± 0.04 |
0.001 |
0.06 |
|
Egg production, % |
87.8 ab±0.8 |
85.2b ± 0.8 |
88.5ab ± 0.8 |
89.6a ± 0.8 |
0.01 |
1.2 |
|
Feed /egg, g /g |
29.3ab± 0.22 |
29.9b ±0.22 |
29.4ab ±0.22 |
28.8a ±0.22 |
0.007 |
0.3 |
|
ab Means in the same row without letter in common are different at P<0.05 |
||||||
Inclusion of 5% of cassava leaf meal in quail diets improved yolk colour, while inclusion of 5% field crab roe improved percent egg production, feed conversion and mean egg and yolk weights.
The author is grateful to the Swedish Agency for Research Cooperation with Developing Countries (SAREC) for supporting this research.
Bui Huy Nhu Phuc, Ogle B and Lindberg J E 2001 Nutritive value of cassava leaves for monogastric animals. International Workshop on Current Research and Development on Use of Cassava as Animal Feed. Khon Kaen University. p31 http://www.mekarn.org/proc-cass/phuc.htm
Duong Thanh Liem 1993 Limiting factors about feed in the intensive systems of raising poultry. Unpublished data
Duong Thanh Liem 1997 Processing and using cassava leaf meal for feeding livestock. Workshop on Vietnamese Cassava. IAS, Ho Chi Minh City
Phong Van My 1994 Experiment with replacing maize by cassava root meal and fermented cassava with Cephalosporium eichhorniae. Unpublished data.