Nutrient content of feedstuffs scavenged by local chickens kept by smallholder farmers in Lilongwe, Malawi

Harriet Gausi¹, Apeh Omede², Edwin P Chang’a³, Timothy Gondwe⁴, John Gibson⁵ and Paul A Iji⁶

¹ Ministry of Agriculture, Department of Animal Health and Livestock Development, P O. Box 2096, Lilongwe, Malawi
harrietgausi@gmail.com
² Livestock Production Center, Tasmanian Institute of Agriculture, University of Tasmania - Launceston, Australia
³ Tanzania Livestock Research Institute (TALIRI), P O Box 352, Uyole, Mbeya, Tanzania
⁴ Department of Animal Science, Lilongwe University of Agriculture and Natural Resources, P O Box 219, Lilongwe, Malawi
⁵ School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia
⁶ College of Agriculture, Fisheries and Forestry, Fiji University, Suva, Fiji Islands

Abstract

The physical and nutrient composition of crop and gizzard plus proventriculus (G+P) contents of the scavenging local chickens was assessed, to establish the daily feed resource for these chickens. A total of 56 chickens of both sexes were assessed in the wet and dry seasons in Mitundu Extension Planning Area, Lilongwe, Malawi. The chickens were between 15 and 20 weeks of age. Female chickens were those that had not yet started laying. The chickens were randomly caught while scavenging in the afternoon between 14:30 and 17:00 hours, were weighed and immediately slaughtered by cervical dislocation. These were de-feathered and eviscerated in the laboratory, and the crop and G+P were harvested and weighed. The contents were emptied, weighed, and physically identified. The contents were dried at 60 ˚C for 48 hours, before doing proximate analysis. Chicken parts were also weighed. Quantitative data were analysed using the general linear model of the analysis of variance through Minitab 17. Comparison was made between sexes and seasons. The results showed that body weights of adult male and female chickens in both seasons were not different (p > 0.05). In the wet season the body weight of male and female chickens was 1059.6 ± 274.6 g and 1061.5 ± 218.8 g, respectively. In the dry season the body weight of male and female chickens was 1295.8 ± 426.3 g and 1166.3 ± 293.0 g, respectively. The crop and G+P contents included grains, household food refuse, plant material, insects/worms, grit, and miscellaneous materials. Season and sex did not influence (p > 0.05) weight of crop or G+P, and types of feedstuffs in the crop and G+P contents were also the same between the two seasons and sexes, although quantities were different between the two seasons. The quantity of maize grain and household refuse was higher in the dry season, than in the wet season. The quantity of green material, on the other hand, was higher during the wet season than in the dry season. The energy content of the crop and G+P contents in male chickens was higher in the wet season (7.5 MJ/kg) than in the dry season (5.8 MJ/kg), while, in female chickens it was the same in both seasons (6.9 MJ/kg). The crude protein content of the crop and G+P contents was higher in the wet season than in the dry season, and, higher in female chickens than in male chickens. Protein content was 97 and 73 g/kg for male chickens in the wet and dry seasons, respectively, and 100 and 86 g/kg in the wet and the dry season, respectively, for female chickens. It is concluded that the nutrient content of the scavenging feed resources (SFR) was limiting in both seasons, except for some amino acids in the wet season, and that shortage in energy, protein or any mineral in the SFR would be area/location-specific depending on the quality and quantity of the SFR.

Keywords: crop, gizzard and proventiculus, nutrient composition, production parameters, viscera organ

Introduction

Local chickens are also known as scavenging chickens because they rely on scavenging for their nutrition. Local chickens grow and lay eggs, relying exclusively on scavenging for their nourishment, with little or no supplementation, and yet nutrient content of the scavenging feed resources (SFR) is predominantly for maintenance and low production (King'ori et al 2007). It has been well documented that there are several factors that influence quality and quantity of the SFR. These factors include number of households, quantity of household waste, produce residues, type of crops cultivated, crop processing, vegetation and the number of local chickens and other livestock species in the area (Gunaratne et al 1993; Sonaiya et al 2002; Sonaiya and Swan 2004; Goromela et al 2008). Gunaratne et al (1993) also reported that the productivity of local chickens is affected when the capacity of SFR is exceeded; yet, this precious resource (SFR) is usually ignored (Gunaratne et al 1993) and its nutrient content is not known (Mwalusanya et al 2002a). However, knowledge of the quality and quantity of the SFR is crucial for the improvement of local chicken feeding management (Mapiye et al 2008). Some studies have shown that the protein content in the SFR is not sufficient for growing birds and that local chickens only meet approximately 73 % of their protein requirement (Magothe et al 2012b). Protein deficiency in the SFR has also been reported by Tadelle et al (2002). Similarly, Goromela et al (2008) reported that the energy content in the SFR is influenced by cereal harvesting and processing, hence in some seasons, energy content is higher than in others. Deficiencies in energy content have been reported by various researchers. For example, Rashid et al (2005) reported calculated metabolizable energy of 11.49 MJ/kg and Hayat et al (2016) 8.46 MJ/kg versus 11.92 MJ/kg requirement of growers (National Research Council 1994). Since the season and crops that are cultivated influence the quantity and quality of SFR, it is anticipated that the quantity and quality of the SFR would be specific to a particular area/location. The diet of local chickens varies with season (Mwalusanya et al 2002a), but this knowledge is limited in Malawi, so it was necessary to conduct a study to assess the composition of the feedstuffs scavenged by local chickens, by physically identifying the feedstuffs scavenged under the free-range system and to determine the nutrient content of the crop and G+P contents.

Materials and methods

Description of the study area

The chickens used in this study were purchased from villages in Mitundu Extension Planning Area in Lilongwe District, Malawi. The area is about 50 km west of Lilongwe city. The District experiences its lowest temperatures of between 3.5 ˚C and 12.5 ˚C in July and highest temperatures of up to 39 ˚C between October and November. Mean annual rainfall ranges from 800 to 1,000 mm (Malawi Government 2011). The people in this area are farmers who practise mixed farming, growing cash and food crops, and rearing different species of livestock. Some of the crops that are cultivated include maize, soybeans, beans, groundnuts cassava and tobacco, while species of livestock kept include cattle, goats, sheep, pigs and poultry, local chickens being the most popular. All livestock are individually housed during the night but communally managed through extensive feeding system during the day. As indicated in Section 3.2.1, Malawi has three seasons, but in the current study, the three seasons were classified into two, wet and dry season, as is generally recognized by farmers.

Management of the birds and samples collected

A total of 56 full-feathered multi-coloured chickens of both sexes were used in the study, 16 in the wet season and 40 in the dry season. The birds were between 15 and 20 weeks of age. Assessment was done twice during the wet season and three times during the dry season. Farmers were reluctant to sell their chickens at the beginning of this study (during the wet season), hence, fewer numbers were used. As a result, it was not possible to assess the significant differences in nutrient content of the crop and G+P contents for individual chickens, since the contents from some of the birds was so limited that there was insufficient material on which to perform chemical analyses. The situation changed during the dry season; hence, more numbers were used. On the day of assessment, the chickens were randomly caught while scavenging in the afternoon between 14:30 and 17:00 hours, weighed and immediately slaughtered by cervical dislocation. These were de-feathered and eviscerated in the laboratory, and crop and G+P were harvested and weighed. The contents were emptied, weighed, and physically identified and categorised. Laboratory work was done at Bunda Campus of the Lilongwe University of Agriculture and Natural Resources, Malawi. The crop and G+P contents were dried at 60 ˚C for 48 hours and pooled together according to sex and season before milling.

Ethical consideration

The experiment was approved by the Human Ethics Committee of the University of New England under approval No. HE16-161. The study was conducted in accordance with the regulations and requirements of the National Health and Medical Research Council (NHMRC 2013) of Australia.

Data collection

Production parameters

Body weight, empty carcass weight (without feet, head and visceral organs) and chicken part weights were recorded using an SF-400 digital kitchen scale (Zhegiang Yubang Weighing Apparatus Co Ltd Zhegiang China). Shank length was measured (before slaughter) using a measuring tape. Relative part weights were calculated in grams per kilogram of live weight. The crop and the G+P were harvested and weighed, and contents were emptied and weighed, physically identified and categorised. Relative part weight was calculated as follows:

Chemical analyses of the crop and G+P contents

The concentrations of crude protein, ether extract, starch and total sugars and all the other component nutrients of the crop and the G+ P contents (except for amino acid contents) were analysed on a dry weight basis. Samples were dried overnight at 70 ˚C prior to fine grinding (Reuter and Robinson 1997) and analyses.

Dry matter

The dry matter content of the crop and the G+P contents was determined by drying the samples in pre-heated (to 105˚C) forced-air convection oven (Qnaltex Universal Series 2000, Watson Victor Ltd, Perth, Australia). Samples were weighed (2-4 g) in duplicate before placing them in the oven for 24 hours. The dry matter content was calculated as the ratio of the dry weight to the pre-dried weight expressed as a percentage.

Crude protein

The nitrogen (N) content of the crop and the G+P contents was determined according to the method described by (Sweeney 1989) according to the Dumas technique using a LECO® FP-2000 automatic nitrogen analyser (LECO corporation, St. Joseph, MI, USA). The crop and the G+P contents samples were weighed between 0.12 to 0.15 g and rolled in aluminium foil crucibles before setting in a LECO nitrogen analyser. Nitrogen was freed by combustion at high temperature in pure oxygen and was measured by thermal conductivity detection. The furnace temperature was maintained at 105 ˚C for hydrolysis of the sample in ultra-pure oxygen. To interpret the detector response as percentage nitrogen (w/w), calibration was conducted using a pure primary standard of ethylenediaminetetra-acetic acid (EDTA). Crude protein content was estimated from the N content, using a factor of 6.25.

Amino acid contents

The amino acid profiles of samples were determined using pre-column derivatisation amino acid analysis with 6-aminoquinolyl-N-hydrroxysuccinimidyl carbamate (AQC) followed by separation of the derivatives and quantification by reversed phase high performance liquid chromatography (HPLC) according to Cohen and Michaud (1993), and Cohen (2001). High performance liquid chromatographic (HPLC) analysis was based on method of Cohen (2001), but adapted to use an ACQUITY Ultra Performance LC (UPLC; Waters Corp. State USA) system. The crop and the G+P contents underwent 24-hour liquid hydrolysis in 6M HCL at 110°C. After hydrolysis, all amino acids were derivatised using the Waters AccQTagTM ultra chemistry (UPLC; Waters Corp. State USA) and detected on a Waters Acquity UPLC at 260 nm (UV). Final quantification was done using the Waters Empower software. The whole of this procedure was done by the Australia Proteome Analysis Facility (APAF), Macquarie University, NSW, Australia.

Ether extract

The fat content of the crop and the G+P contents was determined by Soxhlet method of fat extraction. A spoonful of sample was placed on a pre-weighed No1 Whatman 185 mm filter paper to bring the total weight to approximately 6 to 8 g. This weight less the filter paper weight was the pre-extraction sample weight. The process was repeated for the duplicates. The papers with the sample were rolled, stapled and packed in the Soxhlet tubes. The thimbles containing the samples were then placed in the sample cylinder, which was filled with chloroform, then, the water condenser was turned on. This was left for 48-50 hours, approximately, to undergo 24-25 refluxes. After turning off the unit and cooling, the basket with the samples was allowed to drain excess chloroform overnight. The following day, the samples were removed from the thimbles and placed in an oven at 80˚C for 72 hours. After drying, the samples were weighed, and total fat percentage was calculated as follows:

where, weight of extracted fat = Pre-extraction sample weight - Post-extraction sample weight

Meat fat content was also determined. Pieces from breast meat were pooled together according to sex of the chicken, minced and dried in an oven at 60 ˚C for 48 hours, after which the samples were finely ground for determination of fat as described above.

Total starch

Sugars were determined by gas chromatography (VARIAN, CP-3800, USA) as the alditol acetate derivatives of the monosaccharides. Approximately 100-200 mg of samples were placed in screw-capped glass vials, to which 5 mL of hexane were added. The samples were vortexed, sonicated for 15 minutes and later centrifuged to remove fat. The residue was extracted with 5 ml of an 80:20 ethanol-water mixture at 80 ˚C for 10 minutes to remove free sugars and oligosaccharides. After centrifuging, the supernatant was collected. Hydrolysis, reduction and acetylation of the samples were carried out following the procedures described by Theander and Westerlund (1993). The analysis was done by the Department of Primary Industries, Wagga Wagga Agriculture Institute, Pine Gully Road, NSW, Australia.

Metabolizable energy

Metabolizable energy (ME) was calculated using a formula by McDonaldet al (2011):

ME (MJ/kg) = 0.01551CP + 0.03431EE + 0.01669ST + 0.01301S

where CP is crude protein, EE is ether extract or fat, ST is starch and S is total sugars.

Data analysis

Data were analysed using the general linear model of the analysis of variance through Minitab 17 (Minitab 2014). Differences were observed at p ≤ 0.05. Where there were significant differences between means, Fisher’s coefficient was used to compare the means.

Results

Weight of the wet and dry crop and G+P contents

Season and sex did not influence the weight of the crop and the G+P contents (Table 1). Thus, the weights of the crop and G+P contents were generally the same in both seasons and in both sexes.

Categorization and composition of crop and G+P contents

The crop and the G+P contents were visually identified and categorized into six groups, namely, household food refuse, grains, insects/worms, plant material, grit and miscellaneous materials (Table 2). All the six categories of the identified feedstuffs were found in both male and female chickens in both seasons, but in the wet season, the quantities of grains (maize and legumes), and household food refuse (mainly nsima ) were lower than early in the dry season (Photo 1 and 2, shows contents from individual birds). Availability of green material, however, was higher during the wet season than in the dry season and was scarcest during the mid of the dry season. Insects were also fewer in the dry season.

A. Wet crop contents	B. Wet G+P contents
Photo 1. Profile of the wet crop and G+P contents in early dry season (June) (Photo by Author, 2016)
A. Wet crop contents	B. Wet G+P contents
Photo 2. Profile of the wet crop and G+P contents in mid dry season (August) (Photo by Author, 2016)

Table 3 shows the nutrient contents of the crop and the G+P contents. The energy content of the crop and the G+P contents in male chickens was higher in the wet season (7.5 MJ/kg) than in the dry season (5.8 MJ/kg), while that of female chickens was the same in both seasons (6.9 MJ/kg). The crude protein content of the crop and the G+P contents was higher in the wet season than in the dry season for both male and female chickens, but was higher in females than males in both seasons. The protein content of the crop and the G+P contents for male chickens was 97 and 73 g/kg in the wet and dry seasons, respectively, while that of female chickens was 100 and 86 g/kg in the wet and dry seasons, respectively. The trend was the same for amino acid contents, which were higher in the wet than in the dry season. In the wet season, amino acids were generally the same in the contents from male and female chickens, with slightly elevated levels of aspartic acids, alanine and valine in female chickens. In the dry season, the levels of leucine were slightly higher in the crop and the G+P contents of female chickens than in male chickens.

In the wet season, calcium content was three times higher in female chickens (9.8 g/kg) than in male chickens (3 g/kg), but the values were almost the same in the dry season for male (4.6 g/kg) and female (4.3 g/kg) chickens. On the other hand, in the wet season, the fat content of the crop and the G+P contents of both sexes, was double that of the dry season. Fat content was also higher in male than in female chickens, in both seasons. The fat content of the crop and the G+P contents of male chickens was 66 and 32 g/kg in the wet and dry seasons, respectively, while that of the female chickens was 53 and 23 g/kg in the wet and dry seasons, respectively.

Meat fat content was higher early in the dry season than during mid dry season, for both male and female chickens, and fat content for female chickens was higher than that of the male chickens at both points of assessment (Figure 1). During the early dry season, male chicken fat content was 56 g/kg and female chicken fat content was 62 g/kg, while in the mid of dry season, male chicken fat content was 36 g/kg and female chicken fat content was 50 g/kg.

Figure 1. Meat fat content (g/kg) of local chickens during the dry season

Production parameters

The relative weights of visceral organs are shown in Table 4. Sex and interaction of season and sex had no influence on the weight of visceral organs. In the wet season, however, birds had a heavier liver (p < 0.05), spleen and G+P (p < 0.01) than birds in the dry season. Liver, spleen and G+P of birds in the wet season were 13, 35 and 18 % heavier than those in the dry season, respectively. Heart weight, on the other hand, was not influenced by season.

Table 5 shows the body weight, weight of the empty carcass, shank length, dressing percentage and relative chicken part weights. Generally, the dressing percentage and chicken part weights were higher in the dry season than in the wet season. In the dry season, the breast, thigh, back, and neck weighed 27, 6, 8, and 12 % more, respectively, than in the wet season. However, the wings were 11 % heavier in the wet season than in the dry season. The shanks of male chickens were 14 % longer (p< 0.001), and drumsticks and feet were 15 and 8 % heavier ( p < 0.001) in male chickens than in female chickens.

Discussion

Weight and composition of crop and G+P contents

There were no significant differences in the wet and the dry weight of the crop and the G+P contents between seasons or sexes. It was not surprising then, that body weight of the chickens was also not different between seasons or sexes. Visual observations showed that, in addition to grit, chickens also ingested miscellaneous materials such as metals, buttons, feathers, and other unidentified materials. These non-feed materials could thus increase the weight of the contents and create a gut fill. Some of these materials, besides having no nutritional value, may contain anti-nutritional factors that affect feed quality and health of the chickens (INFPD/FAO/IFAD. 2012. This would also affect nourishment of the scavenging chickens, since they stop eating (nibbling) when the crop and the gizzard are full (Rashid 2003). There were more grains (maize and legumes) and household food refuse in the dry season, just as there were more green material, insects and worms, in the wet season, as reported by Goromela et al (2006). These findings also agree with those of Mwalusanya et al (2002a) who stated that the diet of local chickens is dependent on the surroundings. Chickens would be able to feed on sprouting green grass during the wet season and the grains that were readily available during the dry season, part of which is the harvesting period. The low volume of household kitchen refuse in the wet season could also imply that food is not readily available or is in low supply, in the wet season as compared to the dry season (Goromela et al 2006).

Nutrient composition of crop and G+P contents

The protein content of the crop and the G+P contents was higher in the wet than in the dry season for both sexes, probably because of the higher composition of insects and worms in the wet season than in the dry season. However, generally the nutrient composition of the crop and the G+P contents in the current study was below the requirement of the brown-egg commercial strains (National Research Council 1994). For example, energy content of the crop and the G+P contents of male chickens was 63 and 49 % of the requirement, in the wet and dry seasons, respectively, while that of female chickens was 58 % of the requirement in both seasons. When the values are compared to the nutrient requirement of the age of pullets that were tested in this study, the shortfall in protein content in the wet season would range from 31 to 39 % for male and 29 to 38 % for female chickens, depending on age, the higher value being the shortfall for chickens aged 18 weeks and older. In the dry season, the shortfall was greater than in the wet season, being as high as 48 to 54 % in male and 39 to 46 % in female chickens. A similar trend was observed in lysine and methionine, where in the dry season the shortfall was greater than in the wet season when compared to 4.3 and 1.9 g/kg for lysine and methionine requirement, respectively for brown-egg-laying strains (National Research Council 1994). In the wet season, both male and female chickens were able to meet up to 71 % of their lysine and 47 % of their methionine requirements, while in the dry season, male chickens only met up to 38 % of their lysine requirement and 32 % of their methionine requirement, and female chickens met 45 % of their lysine requirement, and 37 % of their methionine requirement.

It was also interesting to note that, in the wet season, female chickens consumed feedstuffs that supplied more calcium and phosphorus and, hence, there was a higher concentration of these minerals in the crop and the G+P contents of the female chickens than that of the male chickens. Mwalusanya et al (2002a) and Goromela et al (2006) suggested that the differences in mineral content in crop contents could be due to the nutritional requirements of different age groups. It can be assumed therefore that, this was the case in the current study, since female chickens had reached the point-of-lay, hence needed these minerals for egg production. In the dry season, however, the situation was different; calcium and phosphorus contents were almost the same in both sexes. It can thus be speculated that the higher deficiencies in the SFR could have been the cause for female chickens not having access to ‘enough’ feedstuffs to meet their physiological needs. Equally, male chickens were not able to meet their requirements for both calcium and phosphorus in either season.

This study also showed that the SFR was still inadequate during the dry season when crop harvesting is done and maize grain, maize bran, legumes and household kitchen refuse are readily available. This agrees with reports that the extent to which the SFR would meet the nutrient requirements of scavenging chickens is also subject to other factors, such as the size of the flock that is dependent on the SFR (Sonaiya et al 2002; Kondombo et al 2003; Sonaiya and Swan 2004). Similarly, despite the wet season having a diversity of feedstuffs that contributed to improved nutrient composition, this was also not adequate to meet the requirements of the chickens in the age range that was considered in the current study. This study shows that the SFR alone is not adequate for optimal growth and egg production in either the wet or the dry season. Thus, the diet of local chickens needs to be supplemented for improved productivity (Dessie and Ogle 2001; King'ori et al 2007; Momoh et al 2010). It has to be noted that the extent of the SFR deficit in meeting nutrient requirements of the scavenging chickens will be different between areas/locations since the SFR is a product of various factors (Roberts 1991; Gunaratne et al 1993; Sonaiya et al 2002; Goromela et al 2008).

Production parameters

The shanks of male chickens were longer than those of female chickens. Likewise, drumsticks and feet were heavier in male than in female chickens. These differences reflect the higher body size of male chickens than female chickens. Debes et al (2015) reported that shank length influenced body weight, carcass weight and some carcass parts, although at some period (age), the body weights may not be significantly different unlike the results in the current study. These findings also support those reported by Kitso et al (2018), where shanks of male naked neck and normal chickens were longer than those of their female counterparts. On the other hand, season influenced carcass dressing percentage, and hence the weight of some carcass parts. For example, the high dressing percentage during dry season was reflected in some carcass parts.

Conclusion

Notwithstanding the relatively limited sample size in the wet season, this study offers valuable insights into the variation in composition and nutrient content of the crop and the G+P contents and reflects the characteristics of the SFR. This information would help in development of suitable supplementation strategies to complement the inadequate nutrition of the SFR. It is thus concluded that the: composition of feedstuffs scavenged was affected by season, although quantities of the crop and the G+P contents were not influenced by season or sex. Nutrient content of the SFR was limiting in both seasons, except for some amino acids in the wet season. Neither male nor female chickens were meeting their nutrient requirements, except that the SFR would support calcium and phosphorus requirement of female chicken between age group 15 to 18 weeks in the wet season. These findings necessitated a study on evaluation of performance of local chickens managed by community under different supplementation regimes.

References

Cohen S A 2001 Amino acid analysis using precolumn derivatization with 6-aminoquinolyl-N-Hydroxysuccinimidyl carbamate. In: Cooper, C., Parker, N., Williams, K. (eds) 'Amino Acid Analysis Protocols. Methods in Molecular Biology™.' Vol. 159 pp. 39-47. Humana Press. https://doi.org/10.1385/1-59259-047-0:039

Cohen S A, Michaud D P 1993 Synthesis of a fluorescent derivatizing reagent, 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, and its application for the analysis of hydrolysate amino acids via high-performance liquid chromatography. Analytical biochemistry 211:279-287. https://doi.org/10.1006/abio.1993.1270

Debes A A, Hasaan S F, El-Rehem A, HA H, Eshera A A, Bashandy M G 2015 Relationship of shank length with some productive and physiological parameters of matrough chicken strain.Journal of Animal and Poultry Production, Mansoura University, 6(12)741-753. https://doi.org/10.21608/jappmu.2015.52959

Dessie T, Ogle B 2001 Village poultry production system in central highland of Ethiopia. Tropical Animal Health and Production, 33:521-537. https://cgspace.cgiar.org/server/api/core/bitstreams/aa070e3f-bc5e-4033-b632-5f9e71b6dcb8/content

Goromela E H, Kwakkel R, Verstegen M, Katule A 2008 Effect of season and farming system on the quantity and nutritional quality of scavengeable feed resources and performance of village poultry in central Tanzania.Journal of Cell and Animal Biology, 2: 063-071. https://edepot.wur.nl/26732

Goromela E H, Kwakkel R P, Verstegen M W A, Katule A M 2006 Strategies to optimize the use of scavengeable feed resource base by smallholders in traditional poultry production systems in Africa: A review.African Journal of Agricultural Research, 1(4)91-100. https://academicjournals.org/journal/AJAR/article-full-text-pdf/CAE614F36626

Gunaratne S P, Chandrasiri A D N, Hemalatha W A P M, Roberts J A 1993 Feed resource base for scavenging village chickens in Sri Lanka.Tropical Animal Health and Production, 25, 249-257. https://doi.org/10.1007/BF02250880

Hayat N, Solomon D, Meseret M 2016 Chemical Composition of Scavenging Feed Resource of Indigenous Chickens.Asian Journal of Animal Sciences. 10.3923/ajas.2016.182.188

INFPD/FAO/IFAD 2012 Family Poultry interactions with other production systems (forestry, tree crops, annual crops, large animals, fisheries, etc): Nutritional opportunities and constraints. Proceedings of an e-conference International Network for Family Poultry Development/FAO/International Fund for Agricultural Development 16 January - 3 February 2012. https://www.fao.org/4/aq626e/aq626e.pdf

King'ori A M, Tuitoek J K, Muiruri H K, Wachira A M, Birech E K 2007 Protein intake of growing indigenous chickens on free-range and their response to supplementation.10.3923/ijps.2007.617.621

Kitso N, Kgathi P, Mosele T 2018 A study of the growth performance of indigenous Tswana chickens raised under intensive management system. https://elixirpublishers.in/index.php/ahpf/article/view/599/531

Kondombo S R, Kwakkel R P, Nianogo A J, Slingerland M 2003 Effects of local feedstuff supplementation on zootechnic performances and nutritional status of village chickens during the end of the rainy season in bukina faso. Revue d’Elevage et de Médécine Vétérinaire des Pays Tropicaux56(3-4):199-204. https://research.wur.nl/en/publications/effects-of-local-feedstuff-supplementation-on-zootechnic-performa

Magothe T M, Okeno T O, Muhuyi W B, Kahi A K 2012 Indigenous chicken production in Kenya: II. Prospects for research and development.World's Poultry Science Journal, 68(1)133-144. 10.1017/S004393391200013X

Malawi Government, 2011 Lilongwe District Socio-Economic Profile. Lilongwe Malawi. 1-162.

Mapiye C, Mwale M, Mupangwa J F, Chimonyo M, Foti R, Mutenje M J 2008 A research review of village chicken production constraints and opportunities in Zimbabwe. Asian-Australasian Journal of Animal Sciences 21(11)1680-1688. 10.5713/ajas.2008.r.07

McCleary B, Solah V, Gibson T 1994 Quantitative measurement of total starch in cereal flours and products.Journal of Cereal Science, 20 (1)51-58. https://doi.org/10.1006/jcrs.1994.1044

McDonald P, Edwards R A, Greenhalgh J F D, Morgan C A, Sinclair L A, Wilkinson R G 2011 'Animal Nutrition. Seventh Edition.' (Pearson: England). https://eliasnutri.wordpress.com/wp-content/uploads/2020/07/animal-nutrition-7th-edition.pdf

Minitab 2014 Computer software. PA: Minitab Inc., State College.

Momoh O M, Egahi J O, Ogwuche P O, Etim V E 2010 Variation in nutrient composition of crop contents of scavenging local chickens in North Central Nigeria.Agriculture and Biology Journal of North America, 1(5)912-915. https://doi.org/10.5251/abjna.2010.1.5.912.915

Mwalusanya N A, Katule A M, Mutayoba S K, Minga U M, Mtambo M M A, Olsen J E 2002 Nutrient status of crop contents of rural scavenging local chickens in Tanzania.British Poultry Science, 43(1)64-69. https://doi.org/10.1080/00071660120109926

National Research Council 1994 'Nutrient Requirements of Poultry: Ninth Revised Edition, 1994.' (The National Academies Press: Washington, DC)

Rashid M M 2003 Nutritional status of scavenging chickens with special emphasis on energy and protein supplementation under rural conditions in Bangladesh. MSc Thesis, The Royal Veterinary and Agricultural University: Denmark. https://www.researchgate.net/publication/237286070

Rashid M M, Islam, M N, Roy, B C, Jakobsen K, Lauridsen C 2005 Nutrient concentrations of crop and gizzard contents of indigenous scavenging chickens under rural conditions of Bangladesh. Livestock Research for Rural Development 17 article 16. https://www.researchgate.net/publication/280316693

Reuter D, Robinson J B 1997 'Plant analysis: an interpretation manual.' (CSIRO publishing: Victoria, Australia). https://ebooks.publish.csiro.au/content/plant-analysis-interpretation-manual

Roberts J A 1991 'The scavenging feed resource base in assessment of the productivity of Village chickens, Newcastle disease in village chickens: control with theormostable oral vaccines.' Kuala Lumpur, Malaysia. (Australian Centre of International Agriculture Research Canberra, Australia) p 29-32.

Sonaiya E B, Dazogbo J S, Olukosi O A 2002 Further assessment of scavenging feed resource base.IAEA 193-200. https://inis.iaea.org/records/2kdhm-g3q66

Sonaiya E B, Swan S E J 2004 'Small-scale poultry production: technical guide manual. FAO Animal Production and Health 1.' (Food and Agriculture Organistion of the United Nations, : Rome, Italy). https://www.fao.org/4/y5169e/y5169e00.htm

Sweeney R A 1989 Generic combustion method for determination of crude protein in feeds: Collaborative study.Journal-Association of Official Analytical Chemists, 72:770-774. https://pubmed.ncbi.nlm.nih.gov/2808239/

Tadelle D, Nigusie D, Alemu Y, Peters K J 2002 The feed resource base and its potentials for increased poultry production in Ethiopia.World's Poultry Science Journal, 58(1)77-87. https://doi.org/10.1079/WPS20020009

Theander O, Westerlund E 1993 Determination of individual components of dietary fiber. Dietary Fiber in Human Nutrition, 77-98.