 |
|
Figure 1. The hatchlings from the first clutch of seven eggs of Francolinus bicalcaratus collected from the wild, inside the improvised brooder box. |
| Livestock Research for Rural Development 27 (5) 2015 | Guide for preparation of papers | LRRD Newsletter | Citation of this paper |
The natural home range of the African Bush Fowl (Francolinus bicalcaratus) is the rain forest and savannah ecological zones of West Africa to which the bird had hitherto been well adapted. But recently, increased hunting pressures, increased urbanization and construction of access roads to link these urban areas have combined to put a lot of pressure on the home range of this game bird whose economic importance to the local populace is second only to that of Guinea Fowl. If care is not taken, the bird could be hunted out of existence and the local population may lose its culinary delicacy from their menu for ever. Therefore, efforts geared at its preservation through possible domestication and adaptive breeding must be sought.
An experiment was thus conducted on two clutches of seven eggs each collected in the wild from two African bush fowl hens to determine the characteristics, composition and hatchability of the eggs. The egg quality parameters investigated include average egg weight, egg length, egg width, egg shape index, yolk colour score and shell thickness while the compositional studies were on the crude protein, fat, moisture and ash contents of the eggs. Parameters like percentage hatchability, average chicks’ weight, percentage chicks’ weight and egg to chicks’ weight ratio were also determined.
The results showed an average egg shape index of 77.00±0.70% and a mean egg weight of 26.00±0.70g. The average egg length and width were 4.38±0.04cm and 3.37±0.02cm respectively. The yolk colour score was 6.40±0.24 while the average shell thickness was 0.65±0.01mm. The crude protein, fat, moisture, and ash contents of the eggs were, 15.35±0.07%, 11.93±0.77%, 70.90±0.44% and 1.69±0.06% respectively. Percentage hatchability in this experiment was 100, average chick’s weight was 11.81g while the egg to chicks’ weight ratio was 2.25:1 and percentage loss in egg weight during incubation was 54.51±1.53. It could be concluded that African bush fowl holds a lot of nutritional promises that should be explored for the maximum benefits to circumvent the seemingly intractable problem of animal protein malnutrition, especially in sub-Saharan Africa. Also, the 100% hatchability recorded under artificial incubation with the few eggs investigated so far placed African Bush Fowl at a vantage point of improving its reproductive success under captive breeding and eventual domestication.
Keywords: African Bush Fowl, egg characteristics, hatchability, reproductive success
African Bush Fowl, otherwise called double-spurred francolin is a specie of bird that is highly adaptable to the savannah ecological zone of Africa. The francolins belong to the order Galliformes and to the family Phasianidae (Oluyemi and Roberts, 2000). It is a very important game animal that is second only to the guinea fowl in terms of economic importance in this ecological zone. Its relatively high dressing percentage (68%) as reported by Ekue (2001) and the nutritional classification of its flesh as the white meat type makes it a culinary delicacy for both the rich and the poor alike. As a result of this, Francolinus bicalcaratus and other francolin species like the black and grey francolins (Francolinus francolinus henrici and F. pondicerianus interpositus) of Asian sub-continent (Abbasi and Khan, 2004) have been massively hunted over the years even to endangered species status.
Aside from the hunting pressure, the bird’s natural habitat has been largely opened up in recent times to give way for rapid urbanization and extensive road network. Ecological sequestration with a concomitant population isolations and fragmentation (Charalambides, 1994) therefore became the lots of the birds as a result of these human encroachments into their natural habitats. A gradual decline in the population of these birds has thus been witnessed which if not curtailed can culminate in the disappearance of this prized bird from our culinary menu. To save these species of bird for future generation, research efforts geared towards their domestication, nutrition, adaptive reproductive physiology and breeding should be canvassed. This paper reports such supportive research.
Two clutches of seven eggs each, from a fallow farmland within the vicinity of the Teaching and Research Farm of the Federal University of Technology, Akure, Nigeria were collected and taken to the laboratory of the Department of Animal Production and Health of the University. All the eggs were weighed while measurements like the width and length of each egg were taken with aid of vernier callipers. Five of the eggs were subsequently broken in order to determine the eggs’ internal qualities and composition according to the methods described by Aro et al. (2009). Yolk colour score was determined with the aid of the Roche colour fan while egg shell thickness was measured with micrometre screw gauge. The egg shell thickness was measured at three locations on the eggs i.e. at the broad end, narrow end and the equatorial region of the eggs, the average of the three locations was thereafter computed.
Nine of the eggs were taken to Oluade Farms at Ilara-Mokin, Ondo State, Nigeria for incubation and hatching. Chicks were collected upon hatching on the 21st day of incubation, weighed and transferred to the brooding pen specially prepared for them (Figure 1). Figure 2 shows the morphology of a matured African bush fowl’s hen.
|
|
|
Figure 1. The hatchlings from the first clutch of seven eggs of Francolinus bicalcaratus collected from the wild, inside the improvised brooder box. |
 |
| Figure 2. Adult Francolinus bicalcaratus female (Courtesy: AFBID 2009). |
The eggs’ external quality parameters are presented in Table 1. The average weight of the eggs collected from the two clutches was 26.0±0.70g with a coefficient of variation of 2.69%. The low value of coefficient of variation showed that there is low variability in the weight of Francolinus bicalcaratus eggs. The average length of the eggs of Francolin was 4.38±0.04 cm while the average egg width and mean egg shape index were 3.37±0.02cm and 77.0±0.70% respectively. The coefficient of variation of the three external egg parameters also revealed that they are not widely dispersed from the mean values of their different statistics.
| Table 1. External quality parameters of African bush fowl’s eggs | |||
| Egg weight (g) | Egg length (cm) | Egg width (cm) | Egg shape index (%) |
| 25.4 | 4.30 | 3.30 | 76.7 |
| 26.0 | 4.20 | 3.35 | 79.8 |
| 26.0 | 4.26 | 3.31 | 77.7 |
| 25.7 | 4.25 | 3.35 | 78.8 |
| 26.0 | 4.31 | 3.29 | 76.3 |
| 25.9 | 4.30 | 3.35 | 77.9 |
| 25.4 | 4.29 | 3.21 | 74.8 |
| 26.4 | 4.65 | 3.30 | 71.0 |
| 27.7 | 4.50 | 3.55 | 78.9 |
| 27.1 | 4.65 | 3.45 | 74.2 |
| 25.5 | 4.25 | 3.40 | 80.0 |
| 25.8 | 4.65 | 3.45 | 74.2 |
| 26.3 | 4.40 | 3.50 | 79.6 |
| 25.0 | 4.35 | 3.40 | 78.2 |
| Mean 26.0 | 4.38 | 3.37 | 77.0 |
| ±SEM 0.70 | 0.04 | 0.02 | 0.70 |
| C.V.(%) 2.69 | 3.65 | 2.67 | 3.42 |
| ± SEM = ± standard error of the mean; C. V. = Coefficient of variation | |||
Tables 2 shows the internal egg quality characteristics of the African bush fowl. The mean yolk colour index was 6.40±0.24 while the combined egg and its shell membranes had a mean value of 5.41±0.15g. The mean weight of the yolk plus the albumen was 19.6±0.03g while the fresh shell weight, shell membranes and shell thickness had mean values of 4.48±0.02g, 0.95±0.13g and 0.65±0.01mm respectively. The proportion of the combined yolk plus albumen, shell membranes and shell weight to the total egg weight is presented in Figure 3. The yolk plus the albumen accounted for 78% of the egg while the shell membranes and the shell accounted for 4% and 18%, respectively.
| Table 2. Internal quality parameters of African Bush Fowl’s eggs | |||||
| Yolk colour index | Shell + membrane(g) | Albumen + yolk(g) | Fresh shell weight(g) | Shell membrane(g) | Shell thickness(mm) |
| 6.00 | 5.14 | 19.6 | 4.51 | 0.63 | 0.64 |
| 7.00 | 5.84 | 19.6 | 4.44 | 1.40 | 0.66 |
| 6.00 | 5.22 | 19.5 | 4.42 | 0.78 | 0.64 |
| 6.00 | 5.67 | 19.5 | 4.50 | 0.93 | 0.63 |
| 7.00 | 5.16 | 19.6 | 4.52 | 1.02 | 0.65 |
| Mean 6.40 | 5.41 | 19.6 | 4.48 | 0.95 | 0.65 |
| SEM 0.24 | 0.15 | 0.03 | 0.02 | 0.13 | 0.01 |
| C.V.(%) 8.59 | 6.10 | 0.36 | 0.89 | 30.6 | 1.56 |
| ± SEM = ± standard error of the mean; C.V. = Coefficient of variation. | |||||
 |
| Figure 3. Proportion of combined albumen and yolk, shell
membrane and shell to the total weight of the egg of Francolinus bicalcaratus. |
Table 3 shows the composition in terms of protein, fat, ash and moisture content of eggs collected from the African Bush Fowl’s hens. The crude protein averaged 15.4±0.07% while fat, ash and moisture content of the egg were 11.9±0.21%, 1.69±0.03% and 70.9±0.44% respectively. The proportion of these nutritive components in the egg of Francolinus bicalcaratus in Table 3 was clearly depicted in Figure 4 as 71% (moisture), 15% (protein), 12% (fat) and 2% (ash).
| Table 3. Nutrient composition of the eggs of African Bush Fowl (Francolinus bicalcaratus). | |||
| Crude protein | Fat | Ash | Moisture |
| 15.2 | 12.6 | 1.77 | 70.4 |
| 15.6 | 11.4 | 1.60 | 71.5 |
| 15.2 | 12.0 | 1.67 | 70.5 |
| 15.3 | 11.7 | 1.72 | 70.9 |
| 15.5 | 11.9 | 1.69 | 71.2 |
| Mean 15.4 | 11.9 | 1.69 | 70.9 |
| SEM 0.07 | 0.21 | 0.03 | 0.44 |
| C.V. (%) 0.98 | 3.86 | 3.55 | 0.62 |
| ± SEM = ± standard error of the mean; C.V. = Coefficient of variation. | |||
 |
| Figure 4. Percentage composition of protein, fat, ash and moisture in Francolinus bicalcaratus egg. |
Table 4 shows the hatchability parameters of the eggs of Francolinus bicalcaratus collected from the wild. The average weight of the nine artificially incubated eggs was 25.8±0.20g while the chicks’ weight upon hatching averaged 11.8±0.56g. The percentage weight of the chick to that of the egg set was 45.5±1.53 while the percentage loss in egg weight during the entire incubation period was 54.5±0.51.
| Table 4. Hatchability parameters of African bush fowl’s eggs under artificial incubation. | ||||
| Egg weight(g) | Chicks weight (g) | % chicks’ weight | Egg weight:chicks weight ratio | % loss in egg wt. during incubation |
| 25.4 | 10.7 | 41.9 | 2.83:1 | 58.1 |
| 25.0 | 12.1 | 46.5 | 2.15:1 | 53.5 |
| 25.7 | 11.4 | 44.5 | 2.25:1 | 55.5 |
| 26.0 | 12.2 | 46.8 | 2.14:1 | 53.2 |
| 25.9 | 12.0 | 46.4 | 2.15:1 | 53.6 |
| 27.1 | 12.5 | 46.3 | 2.16:1 | 53.7 |
| 25.5 | 11.5 | 45.0 | 2.22:1 | 55.1 |
| 25.8 | 11.9 | 46.0 | 2.18:1 | 54.1 |
| 26.2 | 12.1 | 46.0 | 2.17:1 | 54.0 |
| Mean 25.8 | 11.8 | 45.5 | 2.25:1 | 54.5 |
| SEM 0.20 | 0.56 | 1.53 | 0.07 | 0.51 |
| C.V. (%) 2.28 | 4.74 | 3.36 | 9.78 | 2.81 |
| ± SEM = ± standard error of the mean; C.V. = Coefficient of variation. | ||||
The external egg quality characteristics (Table 1) revealed that the average egg weight of African Bush Fowl is 26.0±0.70g. This is about 2.5 times heavier than the average quail’s (Coturnix coturnix japonica) egg and about half the size of the domestic chicken’s (Gallus gallus) egg. With FAO’s recommendation of an egg/day for the domestic chicken’s egg, a recommendation of two eggs of African bush fowl will suffice to satisfy the animal protein needs of humans. Values (77.0±0.70%) for the egg shape index showed that the Francolinus bicalcaratus eggs are more rotund than the average chicken’s egg. The optimum egg shape index for chicken’s egg according to Laseinde (2011) is 74%. This author reported that values above or below 74% could adversely affect hatchability. Since 100% hatchability was recorded for all the artificially incubated eggs, then the observed egg shape index could not be said to present any adverse effect on the hatchability of eggs from this species of birds. It only shows that the African Bush Fowl’s egg is comparatively wider in dimension than the Gallus gallus domesticus’ egg probably to accommodate more yolk in order to supply more energy for the precocial hatchlings of Francolinus bicalcaratus (Sotherland, and Rahn, 1987).
The yolk colour index (Table 2) was 6.40±0.24 on the Roche colour score, a value that far exceeds the recommendation of the Nigerian Confectionery Association’s standard for yolk colour score (Aro et al., 2009). The very high yolk colour score in this experiment would have resulted from access to carotenoid pigment precursors that the hen that laid these eggs had in the wild. The proportion of the combined albumen and yolk to the egg is 78% in African Bush Fowl (Figure 3) while it is about 89% in the chicken’s egg. The shell accounts for 18% in the Francolinus bicalcaratus while it accounts for 10% in the chicken’s egg (Leeson, 2006) and between 9 and 14% (www.poultrycrc.com.au/). The shell membranes were calculated as 4% of the total weight of the egg in Francolinus bicalcaratus. The values obtained for the shell membranes were widely dispersed from the mean as observed by the relatively high coefficient of variation (30.59%). This was because the shell membranes were not easily detachable and hence fragments of the membranes still got entangled with the shell. The reason that could be adduced for this is that at the stage when the eggs were collected, embryonic development must have been initiated with the possible fusion of the allantoin membrane with the chorion and the two shell membranes. The two shell membranes therefore must at this juncture engage the egg shell in close affinity in order to ensure maximum chorio-allantoic respiration. The shell thickness of 0.65±0.01 mm is thicker than the average (0.33-0.35mm) recorded for Gallus gallus domesticus (Laseinde, 2011). The comparatively thicker egg shell for the Bush Fowl could have accounted for its higher proportion to the total weight of the egg than as observed in the domestic chicken.
The crude protein content (Table 3) of the egg averaged 15.4±0.07%. The fat, mineral and moisture contents were 11.9±0.21%, 1.69±0.03% and 70.9±0.44% respectively. The relatively higher protein and fat content (Figure 4) with a concomitant lower moisture content of the eggs put African Bush Fowl in the category of precocial birds which need a relatively shorter brooding periods than their semi-precocial counterparts (Sotherland and Rahn, 1987). The two clutches of eggs hatched at the 21st day of incubation with 100% hatchability. This was however widely different from 44.0% reported by Khan (2010) for the Black and Grey Francolins of the Asian sub-continent. African Bush Fowl hens thus have the same incubation period as Gallus gallus domesticus which is different from the incubation period of their Asian close relatives Francolinus francolinus henrici and F. pondicerianus interpositus whose average incubation period is 18.53 and 17.68 days respectively (Khan, 2010). Generally, the incubation period of the Francolins reported in the literature ranged between18-21days (Ali and Ripley, 1969; Roberts, 1991; del Hoyo et al., 1994). The clutch size from the two clutches collected in this experiment was seven eggs apiece. Two other clutches collected but not captured in this study had seven and four eggs respectively (personal observation). These four clutches thus had a range of 4-7 eggs with a mean of 6.25 eggs/clutch. Khan (2010) reported a range of 2-12 eggs/clutch for Black Francolin (Francolinus francolinus henrici) and 2-13 for Grey Francolin (Francolinus pondicerianus interpositus) with an average of 6.56 and 7.22 eggs /clutch respectively.
The average chicks’ weight, percentage chicks’ weight, egg weight to chick weight ratio and percentage loss in weight of the eggs throughout the incubation period were 11.8±0.56g, 45.5±1.53, 2.25:1±0.07 and 54.5±0.51 respectively (Table 4). Percentage chicks’ weight at day old was lower in comparison with that of domestic chicken (Laseinde, 2011). No previous data were available on the breeding success of African Bush Fowl either in the wild or under captive breeding. The breeding successes of its close relatives as reported in the literature are 36.0±3.18% and 37.0±3.25% in the Black and Grey Francolin respectively (Khan, 2010) and 31-35% for the Grey Partridge with adult survival rate of 25-30% (Panek, 2005). The 100% hatchability so far recorded under artificial incubation placed African Bush Fowl at a vantage point of improving its reproductive success under captive breeding and eventual domestication.
The authors are grateful for the services of Mr. Lawrence Oluwasanmi of the livestock Section of Teaching and Research Farm of the Federal University of Technology, Akure, Nigeria, who tracked the nestling sites of the birds and helped in the collection of the eggs from the wild.
AFBID 2009 African Bird Image Datapage. afbid@birdexplorers.com Latest page update 8th April 2009.
Abbasi F and Khan J A 2004 Abundance and habitat use of Grey Francolin, Francolinus pondicerianus, in Gursikaran Forest, Aligarh district, Utter Predesh, India. 3rd Internat. Galliformes Symp., India
Ali S. and Ripley S D 1969 Handbook of the Birds of India and Pakistan. Vol.3. Oxford Univer. Press, Bombay, India
Aro S O, Tewe, O O and Aletor V A 2009 Potentials of Chromolaena odorata leaf meal as egg yolk colourant for laying hens. Livestock Research for Rural Development. Volume 21, Article#171. http://www.lrrd.org/lrrd21/10/aro21171.htm
Charalambides M 1994 Black Francolin. In Birds in Europe: Their Conservation Status. Birdlife Conserv. Ser. No. 3, BirdLife Intl. Cambridge, UK. pp. 218-219
del Hoyo J, Elliott A and Sargatal J 1994 Handbook of the Birds of the World. In: Lynx (ed.), New World Vultures to Guinea fowl. Barcelona, pp 412-567.
Ekue M R M 2001 Ecological study of bush fowl (Francolinus bicalcaratus Linnaeus, 1766) and working out pattern for its breeding in strict captivity. Bulletin Bedim, 10, 1
Khan W A 2010 Studies on the comparative ecology of the south Persian Black Partridge, Francolinus francolinus henrici, and the northern Grey Partridge, Francolinus pondicerianus interpositus, in Lal Suhanra National Park, Bahawalpur, Punjab, Pakistan. A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Zoology. Department of Zoology, Faculty of Sciences. Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi-Pakistan.
Laseinde E A O 2011 Hatchery Technology for Poultry Eggs. Copyright © 2011. ISBN 978-33992-4-1
Leeson S 2006 Defining and predicting changes in nutrient requirements of poultry. World's Poultry Science Journal, 62, (Abstracts & Proceedings CD).
Oluyemi J A and Roberts F A 2000 Poultry Production in Warm Wet Climates. Spectrum Books Limited (Publishers), 2nd Edition. Spectrum House, Ring Road, Ibadan, Nigeria. Pp. 1-244.
Panek M 2005 Demography of Grey Partridge (Perdix perdix) in Poland in the years 1991 – 2004: reasons of population decline. Eur. J. Wildl. Res. 51: 14 – 18
Roberts T J 1991 The Birds of Pakistan. Vol. I. Regional studies and non- passeriformes. Oxford Univ. Press. Karachi, Pakistan, p. 598.
Sotherland P R and Rahn H 1987 On the composition of bird eggs. Condor 89: 48-65. www.poultrycrc.com.au/ Poultry CRC, P.O. Box U242, University of New England, Armidale NSW 2351 Australia.
Received 8 March 2015; Accepted 31 March 2015; Published 1 May 2015