Jojoba meal (Simmondsia chinensis) in the diet of broiler breeder pullets: physiological and endocrinological effects.
The present studies evaluated the ability of jojoba meal (JO) to inhibit feed intake of broiler breeder pullets to limit body weight gain as recommended by the breeder company. A first experiment, using graded levels of JO supplementation (0 to 12%), was conducted to establish appropriate JO supplementation. Adequate reduction of growth rate was obtained with 4% JO supplementation. However, notwithstanding their similar growth rate, 4% JO chickens consumed considerably more feed compared with feed-restricted chickens. The dose-dependent impairment of feed intake with increasing levels of JO supplementation was also associated with increased plasma growth hormone and thyroxine and with decreased plasma insulin-like growth factor-I and triiodothyronine concentrations compared with 0% JO chickens. A second experiment included a pair-fed group. Notwithstanding their similar feed intake, 4% JO chickens gained significantly less body weight compared with their pair-fed counterparts. The 4% JO chickens also had a longer feed transit time per kilogram body weight. Again, circulating levels of the somatotrophic and thyrotrophic hormones were altered according to the dietary treatment. From all these observations, it was concluded that the growth retardation caused by JO supplementation was provoked by an inhibition of appetite linked with the simmondsin content of JO as well as by other antinutritional compounds affecting digestibility.
Arnouts
S
S
Laboratory for Physiology and Immunology of Domestic Animals, Leuven, Belgium.
Buyse
J
J
Cokelaere
M M
MM
Decuypere
E
E
D000821:Animal Feed; D000818:Animals; D002645:Chickens / Q000097:blood / Q000254:growth & development / Q000502:physiology*; D004435:Eating; D005260:Female; D005772:Gastrointestinal Transit; D013006:Growth Hormone / Q000097:blood; D006728:Hormones / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D010947:Plants, Toxic; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D006728:Hormones; D014284:Triiodothyronine; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D013974:Thyroxine