Influence of body composition, methionine deficiency or toxicity and ambient temperature on feed intake in the chick

Effect of Methionine Deficiency on the Growth Performance, Serum Amino Acids Concentrations, Gut Microbiota and Subsequent Laying Performance of Layer Chicks

This study was conducted to investigate the effect of methionine (Met) deficiency in the rearing period on the growth performance, amino acids metabolism, intestinal development and gut microbiome of egg-laying chicks and the continuous effects on the performance, egg quality, and serum amino acids metabolism of the subsequent development process. Three hundred sixty one-day-old chicks were randomly divided into two groups and fed on a basal diet (NC group, Met 0.46%) and Met deficiency diet (Met- group, Met 0.27%). Each group included six replicates with 30 chicks per replicate. The trial lasted 6 weeks (0–6 weeks), both groups were fed the same basal diet which met the needs of Met during the observation period (7–24 weeks). Results showed that Met deficiency significantly decreased (P < 0.05) body weight (BW), average daily weight gain (ADG), average daily feed intake (ADFI) and tibia length (TL) compared to the NC group during the trial period (0–6 weeks). Also, Met deficiency dramatically increased (P < 0.05) feed conversion ratio (FCR) during the trial and observation period (7–24 weeks). In addition, during the observation period, the BW and ADG were decreased (P < 0.05) in the Met- group. Moreover, Met- group decreased (P < 0.05) villi height and villi height/crypt depth ratio in jejunum at 6th weeks. In addition, the concentrations of serum main free amino acids (FAA) in the Met- group were significantly increased (P < 0.05) at 6th weeks, while were decreased at 16th weeks. Based on the α-diversity and PCoA analysis in β-diversity, there were no significant differences in the cecal microbial composition between NC and Met- groups. However, the LEfSe analysis revealed that differential genera were enriched in the NC or Met- groups. The Haugh unit, shell thickness and egg production in the Met- group were significantly lower (P < 0.05) than in the NC group. In conclusion, these results revealed that dietary supplementation of appropriate Met could substantially improve the growth performance, host amino acid metabolism and intestinal development and continuously improve the laying performance and thus boost the health of growing hens.

Energy and protein relationships in the broiler. 1. Effect of protein levels and feeding regimens on growth, body composition, and in vitro lipogenesis of broiler chicks

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)

Corticosterone and fat deposition in broiler chicks: effect of injection time, breed, sex and age

1. Corticosterone (680 micrograms/kg body weight per day) given as six daily injections to 3- or 7-week-old chicks decreased weight gain, but increased food consumption, abdominal fat pad weight, skin dry matter, relative liver size and liver fat concentration. 2. Time of day of injection did not modify the response to corticosterone of 3-week-old chicks kept under natural daylight nor of 7-week-old broilers receiving additional illumination. 3. Pure White Rock chicks and Cornish X White Rock crossbred chicks responded similarly to corticosterone at 3 weeks of age. 4. Seven-week-old female birds treated with corticosterone had significantly larger abdominal fat pads than similarly treated males. 5. Corticosterone injection was more effective in increasing the proportion of liver fat in 7-week-old birds than in 3-week-old chicks. 6. The increased amount of abdominal and liver fat due to corticosterone injections administered at 3 weeks of age disappeared after 3 weeks, but growth depression was still evident.

Effect of dietary DL-ethionine on growth and liver metabolism

The effects of DL-ethionine, given in the diet or by injection, on growth, hepatic glycogen and lipids, and the activities of some cytoplasmic NAD-linked dehydrogenases and NADPH-producing enzymes were investigated. 2. Growth virtually ceased after feeding ethionine for 2 d. 3. Ethionine induced an accumulation of lipid, decreased the activities of malic enzyme and isocitrate dehydrogenase and increased the activity of lactate dehydrogenase. 4. The concentration of glycogen in the liver of ethionine-fed chickens increased for 3 d in spite of a decrease in food intake, but then decreased.