Energy and Protein Relationships in the Broiler

Abstract

Male broiler chicks were fed ad libitum diets containing 18, 23, or 30% protein for 3 weeks. In addition, chicks were fed diets containing 12, 23, or 30% protein on a 3-day rotation. Finally, chicks were fed either the 23 or 30% protein on a schedule of 2 days on feed and 1 day off feed. These feeding schemes allowed chicks to consume low to excess protein coupled with either adequate or inadequate energy intake. Feed intakes were equal for the 18, 23, and rotational percent protein dietary groups and lower (P less than .05) for the 30% ad libitum group. Chicks fed the 18% protein diet ad libitum were the least efficient (P less than .05) at utilizing feed and the most efficient (P less than .05) at utilizing protein for weight gain. Compared to the ad libitum situation, restricted feeding improved feed and protein efficiency of chicks fed 30% protein diets but not of chicks fed 23% protein diets. Body composition data on a dry matter basis supported a positive relationship between dietary protein and percent lean tissue. Conversely, expressing data on a whole bird basis indicated that lean body mass was favored by feeding the diet containing 23% protein. In vitro lipogenesis was greatest (P less than .05) in chicks fed a 18% protein diet ad libitum and least (P less than .05) in chicks fed a 30% protein diets ad libitum.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of dietary protein concentrations, amino acids and conjugated linoleic acid supplementations on productive performance and lipid metabolism of broiler chicks

“…Several authors (Fanche & Jensen 1989;Rosebrough & McMurtry 1993) observed that chicks fed low-protein diets had a concomitant increase in carcase fat deposition and, as the liver is the primary site of lipogenesis in chickens (Rosebrough & Steele 1985) the increase of liver percentage observed by the same authors, suggests that the tendency for increased liver weight in chick fed low-protein diets can be related to an increase in lipogenetic activity. In our trial, in general, there are few differences among groups in terms of fat deposition and percentage of liver.…”

Changes in ghrelin mRNA level, plasma growth hormone concentration and performance in different dietary energy and protein levels in broiler chicken

“…Broiler chickens fed increasing energy levels (from 2600 to 3200 kcal ME kg -1 ) showed no significant effects on performance parameters, although there was a decrease in feed intake and an improvement in feed conversion with increasing dietary levels (Waldroup et al, 1990;Attia et al, 2001). Animals fed low energy diets try to obtain adequate energy intake by increasing feed consumption (Rosebrough and Steele, 1985;NRC, 1994). Ghazanfari et al, (2010) reported feed intake and body weight gain increased in broiler fed on low-energy diets compared with those fed on high energy diets during different periods.…”

“…Excessive energy intake is related to the calorie:protein (c:p) ratio in the diet, and consequently, to carcass composition. Isocaloric diets with decreasing protein levels show increasing c:p ratio, which result in carcasses with higher fat percentage (Donaldson, 1985;Rosebrough and Steele, 1985). Armstrong and Britt (1987) showed that changes in energy and protein levels in diets are associated with increased or decreased levels of the concentrations of growth hormone in the blood serum.…”

“…The excess of energy consumed by birds is deposited as fat (Rosebrough and Steele, 1985;Smith and Pesti, 1998). Excessive energy intake is related to the calorie:protein (c:p) ratio in the diet, and consequently, to carcass composition.…”

A Comparison of Various Energy and Protein Concentrations in Diets on the Performance, Bone Mineral Density and Blood Characteristics of Broiler Chicks

“…There was no interaction between dietary energy and protein on blood characteristics, but dietary energy increased from 3,100 to 3,200 kcal/kg in the diet had increased serum glucose level from 237.16 to 281.28 mg/dL (Table 6). So it can be assumed that increased dietary ME and CP increases serum glucose level via two processes (1) an enhancement of de novo lipogenesis (Rosebrough andSteele. 1985, Swennen et al, 2005) and (2) a decreased whole body fat oxidation consecutive to the rise in carbohydrate oxidation (Shah and Garg, 1996).…”