Effects of dietary energy levels on performance and carcass yield of 2 meat-type broiler lines housed in hot and cool ambient temperatures

Abstract

Two meat-type broiler lines, line A and line B were fed experimental diets from 22–42 d with objectives to determine the effects of dietary metabolizable energy ( ME ) levels on feed intake ( FI ), performance, body composition, and processing yield as affected by environmental grow-out temperatures. Two thousand fifty male chicks from line A and 2,050 male chicks from line B were reared in 90-floor pens, 45 chicks per pen utilizing primary breeder nutrition and husbandry guidelines for starter (1–10 d) and grower (11–21 d) phases. Experimental finisher diets consisted of 5 increasing levels of apparent nitrogen corrected ME (2,800, 2,925, 3,050, 3,175, and 3,300 kcal/kg set at 19.5% crude protein and 1.0% dLys at each level) to represent 80, 90, 100, 110, and 120% ME of Evonik AminoChick energy level giving 2 × 5 factorial design and were fed from 22–42 d. All other amino acid levels in diets were formulated to a fixed ratio of dLys level. There were nine replicate pens for each diet and each line. The experiment was conducted twice—once in hot season (barn averages: 77.55 ˚F and 86.04% RH) and another in cool season (barn averages: 69.91 ˚F and 63.98% RH) of the year. Results showed that FI and feed conversion ratios ( FCR ) decreased ( P < 0.05) linearly (R 2 = 0.9) by 61.25 g and 0.073 units for every 10% increase in dietary ME for combined analysis of lines and seasons. The % fat mass of total body mass increased by 0.57%, whereas % protein mass decreased by 0.21% across ME levels (R 2 > 0.9). However, there was no difference ( P > 0.05) in % weights (of live weight) for wings, breast filet, tenders, or leg quarters across ME levels for both lines except % fat pad that increased ( P < 0.05) by 0.20% for each 10% increment in dietary ME level. Line B had higher cumulative FI, BW gain, % lean, and protein mass of body mass than line A in hot season ( P < 0.05). Feed intake was not different between lines in cool season ( P > 0.05), whereas higher BW and improved FCR were observed for line A. Line A had higher % fat mass in both seasons. In summary, performance and yield results as affected by dietary ME levels were line specific and were affected by grow-out seasons. The optimal dietary ME level for the ME range studied (2,800–3,000 kcal/kg) at a constant recommended amino acid level lies in determining the best performance and profitability indices by taking into account the grow-out production inputs and processing yield outputs.

Does modern broilers need less energy for better growth and intestinal development?

“…Improvement in BW and FCR by increasing dietary amino acid density has been documented (Maharjan et al, 2020(Maharjan et al, , 2021Vieira & Angel, 2012). In the current study by decreasing dietary energy level the density of amnio acids (Lysine and total sulphur amino acids) increased per unit of energy which had a possitive effect on chicken's final performance.…”

“…Aftab (2019) reported that the modern broiler chickens need less ME than that recommended by breeder companies. Different studies have proven that the proper ratio of dietary energy to protein/amino acid is very vital for optimal performance of broilers (Maharjan et al, 2020, 2021). Improvement in BW and FCR by increasing dietary amino acid density has been documented (Maharjan et al, 2020, 2021; Vieira & Angel, 2012).…”

“…Different studies have proven that the proper ratio of dietary energy to protein/amino acid is very vital for optimal performance of broilers (Maharjan et al, 2020, 2021). Improvement in BW and FCR by increasing dietary amino acid density has been documented (Maharjan et al, 2020, 2021; Vieira & Angel, 2012). In the current study by decreasing dietary energy level the density of amnio acids (Lysine and total sulphur amino acids) increased per unit of energy which had a possitive effect on chicken's final performance.…”

The Relationship between Performance, Body Composition, and Processing Yield in Broilers: A Systematic Review and Meta-Regression

“…The influence of the varying conditions was intentionally not assessed to avoid misleading inferences based on insufficient statistical power. However, all effect sizes came from factors tested within the same genetic line; therefore, the generalizations in our study do not include relationships among genetic lines [ 64 , 65 , 66 ].…”

Impact of Maggot Black Soldier Fly (Hermetia illucens) Flour Supplementation in Broiler Chickens

“…The treatment of each study uses a temperature that does not exceed the temperature that has been mentioned so that the energy content of metabolism is neither too high nor too low. According to Maharjan et al (2021), dietary energy levels affect energy retention efficiency. The metabolic energy requirement of the finisher ration is 2800-3200 kcal/kg.…”