Effect of Dietary Protein Level and Monensin on Performance of Chicks

Abstract

Four experiments were conducted to investigate a possible interaction between dietary protein level and monensin on growth performance of young chicks. Crossbred chicks (New Hampshire X Columbian) or commercial broiler chicks (Hubbard X Hubbard) were fed corn-soybean meal diets containing various protein levels with or without added monensin (160 or 121 mg/kg). Monensin had little or no effect on growth performance of crossbred chicks fed diets containing 24 or 20% protein. However, growth performance of chicks fed 16% protein diets was depressed 15 and 8% by 160 and 121 mg/kg monensin, respectively. With commercial broiler chicks a marked interaction was observed between dietary protein level and monensin. As dietary protein level decreased, the depression in performance from monensin increased. At 24.0, 21.5, 19.0, and 16.5% protein, weight gains at 4 weeks of age were depressed 20, 29, 35, and 45% by 160 mg/kg monensin and 7, 14, 19, and 28% by 121 mg/kg monensin, respectively. Linear regression analysis indicated that 121 mg/kg monensin depressed growth rate an additional 2.7% for each 1% reduction in dietary protein level. A large portion of the growth depression from monensin could be explained by reduced feed intake. The results of this study indicate that level of dietary protein has a profound effect on the magnitude of growth depression caused by addition of monensin to chick diets. Thus, deficient levels of dietary protein should be avoided when using this anticoccidial drug in broiler feeds.

Effect of growth promoters on monensin toxicity in broiler chicks1

“…According to other data, the effect of monensin on food efficiency is not consistent. It was not affected in studies reported by Christmas and Harms (1984), Welch et al (1986) and Bartov (1987), while in others (Bartov and Jensen, 1980;Parsons and Baker, 1982;Parsons et al, 1984;Bartov, 1987) C, E and R: nutrient consumed, excreted and retained, respectively. 4 RR: relative retention.…”

“…In contrast, however, the adverse effect of monensin on the absolute retention of nitrogen (Table 3) was not caused merely by its effect in reducing food intake, because it also decreased the RR of nitrogen, probably by interfering with nitrogen metabolism. This finding may partly explain why the toxicity of monensin can be reduced by inceasing dietary protein concentration (Parsons and Baker, 1982;Parsons et al, 1984;Welch et al, 1986).…”

“…The depressing effect of monensin on growth is mainly caused by its effect in decreasing food intake (Parsons and Baker, 1982;Welch et al, 1986;Bartov, 1987). The toxicity of monensin to young chicks might be dependent on various dietary factors such as dietary ingredients (Bartov and Jensen, 1980), type of fat (Bartov, 1987) and concentrations of protein (Parsons and Baker, 1982;Parsons et al, 1984;Welch et al, 1986) or fat (Bartov, 1987).…”

Performance of two 1970s and Ross 308 broiler strains fed drug-free low-protein and recommended-protein diets

“…The effect of dietary protein on broiler performance was reported by Fraps as early as 1943 [31]. Parsons and Baker [32] found a positive growth rate attributable to increased dietary protein levels. In the current study, however, the magnitude of reduction in performance attributable to the reduction in dietary CP was greater for the RS strain than for the BS1 or BS2 strains, resulting in an interaction between strain and dietary CP level on BWG.…”

Effets de l’amprolin-300 Ws sur quelques paramètres de croissance et de reproduction chez le lapin mâle (<i>Oryctolagus cuniculus</i>)

“…Courtens et al (1998) ont montré que la plupart des antibiotiques inhibent ou réduisent la spermatogenèse chez les petits ruminants (béliers et boucs). Par ailleurs, les anticoccidiens dans une ration déficitaire en protéines, sont responsables d'une baisse de gain de poids, consécutive à une baisse de la consommation d'eau et d'aliment, aussi observée chez le poulet lors d'utilisation simultanée de certains macrolides (érythromycine) et des sulfamides (Parson et Baker, 1982). Ces données restent partielles et limitées seulement à quelques anticoccidiens et à quelques espèces.…”