ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ผลของการจำกัดอาหารต่อระดับสเตอรอยด์ฮอร์โมนพื้นฐานและการไข่ในไก่ไข่

สื่อสิ่งพิมพ์:pdf

Abstract

The effect of feed restriction on basal steroid hormone levels, and egg production in the layer was studied. Two feed restriction programs; in which the 12-week-old chickens had access to feed for 8h a day (8h-fed group), and had each day for 85% of the calculated amount of feed consumed by the conventional full fed (85%-fed group), were compared with a free-feeding program in which the chicken received the same diet but on an ad libitum basis (ad libitum group). The results showed that serum progesterone and estradiol levels of the three groups were generally increased with age from growing to laying period. The 8h-fed and 85%-fed groups were inclined to have lower levels of progesterone and estradiol than the ad libitum group. Testosterone content, on the other hand, showed no certain pattern of change with either the age or feeding program. Whereas the feed restriction did not affect the age, body weight, and egg weight at the onset of lay, it resulted in delay on age, a heavier body weight and a larger egg size at the 50% egg production. The effect on hen-day egg production was obvious. From the onset of lay to 40 weeks of age, the ad libitum, 8h-fed, and 85%-fed chickens laid 89.7, 61.0, and 49.9 eggs/bird, respectively (p<0.05). The depressing effect on egg production was lifted once the restricted birds were turned to the full feeding. The cumulative number of eggs produced during the period from 40-72w. of the 8h-fed turned full-fed, and 85%-fed turned full-fed groups were 143.9 and 155.2 eggs/bird, respectively compared with the 128.0 egg/bird of the ad libitum group (p<0.05). A similar depressing effect of feed restriction was also true on the feed conversion rate (kg. feed consumed/kg. egg produced).

Article Info

Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 026, Issue 4, Oct 92 - Dec 92, Page 384 - 392 |  PDF |  Page

ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ผลของการจำกัดอาหารต่อการเจริญเติบโตพัฒนาการของรังไข่และท่อนำไข่ และอัตราการตายในไก่ไข่

สื่อสิ่งพิมพ์:pdf

Abstract

The effects of two feed restriction programs, in which the chickens were fed for 8 hours a day (8h-fed group) and fed for eighty-five percent of the amount consumed by full-fed chickens (85%-fed group), and of conventional free feeding program (ad libitum group) on growth, development of ovary and oviduct, and mortality rate in the layer were studied. The results showed that the two feed restriction programs caused a delay in growth and a deterioration in feed conversion rate. Body weight of the 8h-fed group was lower than that of the ad libitum group at 16w. (1271g VS 1384g, P<0.05) whereas that of the 85%-fed group was lower at both 16w. (1293g VS 1384g, P<0.05) and 20w (1479g VS 1550g, P<0.05). Changing a half each of the 8h-fed and 85%-fed groups to the full feeding, and a half of the adlibitum group to the 85% feeding resulted in no significant change in body weight in any but the 85%-fed group. The 85%-fed turned full-fed bird was heavier than the remained 85%-fed bird (1861g VS 1689g, P<0.05) with higher content of the abdominal fat (107g VS 39g, P<0.05). Development of the ovary and oviduct was generally depressed by the 85% feeding program, though the difference (P<0.05) was observed only at the age of 40w. The ovary weight, oviduct weight and oviduct length of the 85%-fed group were 13.0g, 22.3g, and 59.7cm. compared with 37.2g, 53.6g, and 104.0cm of the ad libitum group and 43.0g, 55.9g, and 101.3cm. of the 8h-fed group, respectively. The three groups showed a similar number of small (diameter<2mm.) and medium (diameter 2-8mm.) follicles (P>0.05). Only the number of large follicle (diameter>8mm.) was negatively affected by the 85% feeding program. At 40w, the average number of 1.7 units of large follicle observed in the 85%-fed group was lower (P<0.05) than 5.7 and 6.0 units found in the 8h-fed and ad libitum groups, respectively. The number was, however, increased to equality with those of the other two groups after being switched to the full feeding.

Article Info

Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 026, Issue 3, Jul 92 - Sep 92, Page 263 - 271 |  PDF |  Page