The objective of this work was to define the effects of
dietary energy intake on broiler fat deposition and
metabolism. Fatty broilers are one of the major problems in
the broiler industry.
The effects of changing calorie to protein (Cal/Pr)
ratios, and the addition of cellulose or dried distiller's byproduct
(DDBP) in the diet, on abdominal fat deposition, liver
lipogenesis and glucose oxidation and broiler performance
indicated that the mean body weight of broilers fed narrower
Cal/Pr ratio diets (124 and 143 for starter and grower,
respectively) were lower (P<.01) than broilers fed diets with
mid-Cal/Pr ratios (138 and 160) and wide Cal/Pr ratios (147
and 171). Feed conversion was better (P<.01) for broilers fed
the diet with wide Cal/Pr ratio than the broilers fed the diet
with narrow Cal/Pr ratio. Abdominal fat deposition increased
(P<.001) with wide Cal/Pr ratio than narrow Cal/Pr ratio. No
significant differences were found in in vitro liver
lipogenesis and glucose oxidation when Cal/Pr ratio was
widened. Mean body weight, feed conversion and abdominal fat
levels of broilers fed 5% cellulose or 10% DDBP diets were not
different when compared to broilers fed diets with the same
Cal/Pr ratio without these two feed ingredients.
The time-course of the deposition of abdominal fat
fitted a negative exponential growth curve. The data also
indicated that the highest potential for abdominal fat
deposition was during the first two weeks of age. When the
feed intakes of broilers were restricted for a 6 day period
beginning at 1, 2, 3 and 4 weeks of age, the feed efficiencies
of all the restricted broilers were significantly improved
compared with broilers fed ad libitum. No significant
differences were observed in mean body weight between the
different treatments. The percentage of abdominal fat in
broilers restricted-fed starting either at 1 or 2 weeks old
for a 6-day period were lower (P<.05) than broilers fed ad
libitum. Feed restriction from days 7 to 12 reduced the
adipocyte size but not the number. Feed restriction decreased
(P<.05) lipogenesis at 2 and 8 weeks of age. No significant
effects were found in lipolysis between the restricted and ad
libitum-fed broilers. These studies demonstrate that early
feed restriction (days 7 to 12) reduced abdominal fat
deposition which is attributed to the reduction in the
adipocyte size. Smaller size adipocyte resulted from
decreased activity of lipogenesis. / Graduation date: 1991
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37425 |
| Date | 07 December 1990 |
| Creators | Zhong, Cheng |
| Contributors | Nakaue, Harry S. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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