|Livestock Research for Rural Development 11 (3) 1999
Citation of this paper
[Editors' Note: This article was published originally in the First INFPD / FAO Electronic Conference on Family Poultry (Editor: Gueye Fallou) and is reproduced with the permission of the editors of INFPD and the authors]
The concentrations of major nutrients were determined in crop and gizzard contents of family poultry in different localities and seasons in Bangladesh. In all locations, crude protein content was higher in summer, in comparison with the two other seasons, but was lower than recommended standards. In all locations the crude fibre content was found to be about double the theoretical minimum standard. The calcium (Ca) content of the feed in the different locations was found to be close to the standard requirement for laying hens. However, phosphorus (P) was deficient implying that there was an imbalanced Ca/P ratio in the feed. The most common feed items found in the crop and gizzard were whole rice grain, boiled rice and vegetable materials.
In 1997-98 the small-scale family poultry system in Bangladesh has been estimated to account for about 80 percent of the total poultry population. It is one of the most important income-generating activities for rural women, landless poor and marginal farmers. Bangladesh has a large potential to increase meat and egg production through improvements of indigenous practices in extensive family poultry production systems. This potential is closely linked to an appropriate use of the locally available feed resources. The nutritional status of scavenging laying hens is not known. A balanced ration, which meets the nutritional requirement, is considered to be a prerequisite for an efficient production. However, any adaptation or improvement programme using exotic chickens requires higher inputs of nutrients compared with systems based on local birds (Sazzad 1993).
Before proposing any comprehensive programme for the improvement of family poultry production systems, it is essential to know the existing nutritional status of the feed obtained by hens that scavenge during the daytime. The present study was undertaken to determine the levels of the major nutrients present in the feed taken from the crop and gizzard of laying hens managed in a scavenging system.
On the basis of the country's topography and ecology, five locations were selected from different ecological zones (plane, low, high, hilly and saline land) and areas. The areas were Savar Thana of Dhaka district, Sadar Thana of Sylhet district, Birgonj Thana of Dinajpur district, Hathazari Thana of Chittagong district and Botyaghata Thana of Khulna district. To determine the nutritional status of laying hens under scavenging conditions, an oesophageal crop study was conducted in three seasons (October-January, February-May and June-September that were considered as winter, summer and rainy season, respectively). The numbers of laying hens sacrificed were 107, 98, 100, 95 and 100 at Savar, Sadar, Birgonj, Hathazari and Botyaghata Thanas, respectively. The birds were collected directly from farm households during the scavenging period at 9:30, 11:30, 13:30 and 15:30 hours. They were weighed and sacrificed on the spot by bleeding at the cervical region. The sacrificed birds were carried to the Thana (lowest administrative unit) veterinary hospital / laboratory. The internal organs were opened and the feed in the crop and gizzard was weighed and the feed items identified through eye observation and kept in the deep freezer. After freezing, the feed samples were brought to the laboratory of the Bangladesh Livestock Research Institute. The feed samples were ground and mixed prior to analysis proximate components according to AOAC (1960). The ground samples were weighed and digested with an acid mixture (two parts by weight H2SO4: one part HCIO4) for determination of calcium and phosphorus. When digestion was complete the content was transferred to a 50 ml volumetric flask and made up to the mark using de-ionised water. The phosphorus in the digest was determined by adding ammonium molybdate and ammonium vanadate (Burtons solution) and measuring the colour with a spectrophotometer at 440 µ (Chapman and Pratt 1961). Calcium was determined directly in an atomic absorption spectrophotometer.
The data were analyzed using General Linear Model Procedure of the SAS Programme (SAS/STAT User's Guide, 1988). The test of significance was made according to Kramar (1956).
In each location, it was observed that the crude protein (CP) content of the feeds was highest (P<0.05) during the summer (Table 1; Figure 1). Among locations, the highest level of crude protein was found in Botyaghata.
|Table 1: Chemical composition of collected feed samples of hen in respect to season and location.
|Means with different superscripts in the same column differ significantly (P<0.05)
The higher CP content in the summer season might be due to the greater availability of pulses and insects compared with the other two seasons of the year. This result is in agreement with the findings of Savory et al (1978) who found that the diet of scavenging chicks contained about 56 percent of invertebrate food during the summer period which declined later. The lowest value of CP content (7.31%) was observed in Hathazari region during the rainy season, followed by Sadar (7.75%). Hathazari is a hilly area and the Sadar location is a water logged area. In the rainy season, the birds cannot scavenge properly due to heavy rainfall, which might be the reason for lower CP in these locations.
The crude fibre (CF) content in crop and gizzard contents of birds in Botyaghata was higher (P<0.05) than in all other locations but the effect of season was not consistent. Botyaghata is the most intensive rice producing area among the five locations, and rice is the main crop. It is assumed that the hens in this area get more whole rice grain, which might be the cause of the higher CF content in their scavenged feed. In all seasons and locations the overall CF content of the scavenged feed was higher than is recommended for optimum performance.
Levels of ether extract were low in all locations and seasons with no obvious trends among them. Ash contents were high in all locations and seasons with calcium levels in the recommended range (Figure 3). Phosphorus levels were only slightly lower than recommendations (Figure 4).
The calcium (Ca) content in Botyaghata location during the summer and the rainy season was higher (P<0.05) than in Savar throughout the year. When a particular location was considered it was found that Ca content did not differ in different seasons of the year. It was also observed that there was not much difference in Ca content of the feed of scavenging laying hens among the locations (Savar excepted), and it was very close to the standard requirement for laying hens. The phosphorus (P) content in Savar location was higher (P<0.05) than in all other locations and in all seasons. It was found that the P content in the feed of scavenging laying hens was lower than the standard requirement for laying hens. Thus, the Ca/P ratio did not appear to be balanced in the scavenged feed.
The feed items found in the crop and the gizzard of sacrificed birds are shown in Table 2. Practically the common feed ingredients and wastes picked up by the hens were those available at the homestead of the farmers. The most common items found in the crop and gizzard were rice polishings, whole rice grain, broken rice and boiled rice. Whole wheat, pulses and insects were found in a particular season of the year depending on the crop pattern and rainfall.
|Table 2: List of feed items found in the crop and gizzard of family poultry
|Whole rice grain
|Un-identified feed particles
The results revealed that the feeds scavenged by laying hens are deficient in protein and phosphorus. This has negative effects on production. Huque and Ukil (1993) found that supplementation of laying ducks under scavenging conditions doubled the egg production. On the other hand, Huque and Ukil (1992) reported that although supplementation of scavenging hens increased egg production, this was not cost effective with the existing prices of feedstuffs.
From the results, it may be concluded that the nutrients obtained by hens from scavenging around the homestead in a range of locations in Bangladesh were not enough (protein), or were too high (fibre), or were imbalanced (calcium and phosphorus) when considered in the light of known nutrient needs for high egg production. There were differences among seasons with summer being most favorable, and the rainy season least favorable, in terms of nutrient availability. Protein appeared to be the most limiting of the nutrients.
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