Energy and protein dilution in broiler breeder pullet diets reduced offspring body weight and yield

T.G.V. Moraes, A. Pishnamazi, I.I. Wenger, R.A. Renema, M.J. Zuidhof, Energy and protein dilution in broiler breeder pullet diets reduced offspring body weight and yield, Poultry Science, Volume 98, Issue 6, 2019, Pages 2555-2561, ISSN 0032-5791, https://doi.org/10.3382/ps/pey603

broiler breeder, offspring performance, peer-reviewed, Publication

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Awareness about the importance of maternal diet on offspring health is increasing. Maternal nutrition is being studied in livestock species as a way of improving offspring growth and production. The objective of this research was to evaluate the effect of different dietary energy and protein levels in broiler breeder female rearing diets and different dietary energy levels during lay on offspring growth, carcass yield, and FCR.

Approach

The effect of maternal nutrition on broiler performance was studied using a 2 × 2 × 2 × 2 factorial arrangement of treatments with 2 maternal dietary ME levels during rearing (HEREAR: 2,736 kcal/kg and LEREAR: 2,528 kcal/kg); 2 maternal dietary CP levels during rearing (HPREAR: 15.3% and LPREAR: 13.7%); 2 maternal dietary ME levels during lay (HELAY: 2,900 kcal/kg and LELAY: 2,800 kcal/kg), both with 15% CP and 2 broiler sexes. Broiler breeder hens were artificially inseminated at 35 wk of age. Eggs (n = 1,250) were collected during the following week. All eggs were weighed individually, identified by hen and date laid, and incubated. Broiler chicks (n = 933) were individually identified and placed, 25 to 32 per pen, depending on the numbers hatched in each treatment, into 32 pens. Broilers were weighed weekly. A total of 201 birds were processed at 40 D. Carcass, breast muscle, legs and wings weight were reported as percentage of live BW. Carcass weight did not include viscera, neck, feet, or abdominal fat pad.

Analysis of Results

There was a correlation between maternal 35 wk BW and broiler 39 d BW (r = 0.10; P = 0.03). The most consistent contributor to increased BW was the highest combination of both maternal dietary CP and ME during rearing. Hens on the LEREAR × HPREAR maternal diet had the highest daily maternal protein intake (8.5 g protein/kg BW0.75). As a consequence, upon switching to laying phase diets, any increase in the protein intake for this rearing treatment would have been minimal. During lay, higher protein intake, which occurs as a result of lower maternal dietary ME level, may provide some advantage in terms of greater offspring BW, as relative BW was 1% higher across the LELAY treatment, compared with the HELAY treatment (100.5 vs. 99.5, respectively). The data suggest that a low maternal dietary protein signal at the time of transition to the laying diet may reduce female offspring growth rates. Broilers from the HEREAR × HPREAR treatment had the highest overall carcass yield. Broiler FCR up to 39 d of age ranged from 1.60 (HELAY) to 1.62 (LELAY) but was not significantly influenced by maternal dietary energy during lay (P = 0.65), broiler sex (0.86), or the interaction of maternal dietary energy during lay and broiler sex (P = 0.59).

Application

Effects of maternal rearing diet on the BW of their broiler offspring were sex dependent and transient, but significant. High (15.3%) maternal dietary protein during rearing showed the most consistent overall greatest BW and economically important yields. The low maternal ME level during lay (2,800 kcal/kg) had consistently higher BW, but may have negative effects on offspring yield, particularly in males. Maternal nutrition influenced broiler yield, and thus may be more economically important than previously thought. The results from the current study confirm that maternal nutrition during the broiler breeder pullet stage can impose a lasting influence on offspring BW, which is greater in magnitude than those resulting from laying phase nutrition. This may be the result of more intense feed restriction during the pullet phase, and it suggests epigenetic mechanisms may be in play. A systematic and careful investigation is needed to complete our understanding of these interacting and time-confounded effects and their underlying mechanisms.

Abstract

The objective of the current research was to evaluate transgenerational effects of maternal dietary energy and protein on growth, efficiency, and yield of broiler offspring. A factorial arrangement of treatments consisting of high and low ME and CP levels fed during the rearing and laying phases was used. The study was a final 2 × 2 × 2 × 2 factorial arrangement of treatments, including broiler sex. Ross 708 broiler breeder pullets (n = 933) were fed diets containing 2,736 (HE_REAR) or 2,528 kcal/kg ME (LE_REAR) with either 15.3% (HP_REAR) or 13.7% CP (LP_REAR). From 25 wk, dams were fed a 15% CP laying diet containing 2,900 (HE_LAY) or 2,800 kcal/kg ME (LE_LAY). Following artificial insemination of the dams at 35 wk, eggs were collected for 1 wk, incubated, and pedigree hatched to preserve maternal identity. Broiler offspring were placed sex-separately into 32 pens, according to laying phase maternal treatments, with rearing maternal treatments nested within pens. Individual BW and pen level feed intake were recorded weekly. Broilers were processed at 40 d of age to evaluate yield. Maternal diet effects on offspring BW were sex dependent and transient. Female LP_REAR × LE_LAY broilers had lower pectoralis major and carcass yield than HP_REAR × LE_LAY females. Male HP_REAR × HE_LAY broilers had increased breast yield (19.8%) compared with 18.4% in HP_REAR × LE_LAY broilers. Carcass yield was lower in LE_REAR × HP_REAR broilers (63.7%) compared with HE_REAR × HP_REAR broilers (64.9%). LE_REAR × HP_REAR dams had the lowest ME to CP ratio (E: P) diets and highest rearing phase CP intake. Maternal diet did not influence offspring FCR. The most consistent contributor to increased BW was higher maternal dietary CP and ME during rearing. Low ME maternal laying phase diets increased BW of male offspring more consistently than of female offspring. Maternal nutrition also influenced broiler yield, and is thus economically important. Energy and protein dilution in broiler breeder pullet diets may have detrimental effects on offspring performance.