effects of maternal dietary energy restriction on fat deposition of offspring

Received 16 December 2013Supported by the Education Department Research Program of Heilongjiang Province (12531036); Doctor Science Foundation of Northeast Agricultural University (2009RC28)Li Jin-feng (1987-), male, Master, engaged in the research of animal nutrition and feed science. E-mail: [email protected] * Corresponding author. Xu Liang-mei, Ph. D, professor, engaged in the research of animal nutrition and feed science. E-mail: [email protected]

Effects of Maternal Dietary Energy Restriction on Fat Deposition of Offspring

Abstract: The study was carried out to investigate the effects of maternal dietary energy restriction on growth performance, serum

indices and fat deposition of offspring. A total of 400 female Arbor Acres (AA) broiler breeders were studied. These female birds

involved three experimental treatments and a control group with normal dietary energy diets (ND, 11.7 MJ of ME • kg-1 during the

laying). In treatments 2, 3 and 4, the energies of diets were 20%, 30% and 50% (LD20, LD30 and LD50) lower than those of the

control, respectively. The study commenced at the beginning of the laying period when the total egg production reached 5% of the

flock. All the broiler offspring were fed the same diets. The results showed that in low energy diets, offspring showed decreased

1-day-old weight, but 49-day-old weight was higher in LD20 diet (P<0.05). For offspring during days 1-49, the average daily gain

(ADG) in LD20 group and the feed conversion ratio in LD50 group were improved as compared with those of the control (P<0.05).

Compared with the control, abdominal fat percentage increased in 49-day-old offspring from LD30 diet (P<0.05); the fat content of

breast muscle in offspring increased in broilers fed low energy diets (P<0.05). In 28-day-old offspring from breeders given LD20 and

LD50 diets, liver fat percentages were higher compared with ND (P<0.05). The subcutaneous fat thickness in 28-day-old offspring

from LD50 group and 49-day-old offspring from LD30 group was higher (P<0.05). On day 49, the serum cholesterol (CHO) of

offspring from breeders fed LD20 diet and serum high-density lipoprotein (HDL) of offspring from breeders fed LD50 diet reduced

compared with those of the control (P<0.05). In addition, a higher triiodothyronine (T3) content in serum was found in offspring from

broiler breeders given LD20 and LD30 diets (P<0.05). Serum thyroxine (T4) in offspring significantly decreased with the decrease of

diet energy (P<0.05). In conclusion, to a certain extent, dietary energy restriction in breeders could improve growth performance and

promote lipid metabolism of offspring.

Key words: energy restriction, growth performance of offspring, blood indice of offspring, broiler breeder, fat deposition and

metabolism

CLC number: S831.5 Document code: A Article ID: 1006-8104(2014)-02-0046-07

Introduction

With the rapid development of poultry industry, decline of meat quality and energy waste is being more and more serious. For broiler breeders, diet energy could affect egg quality, and then may influence

embryo development, early growth and fat metabolism in offspring (Tian et al., 2012). Broiler chicken perfor-mance is highly dependent on the genetic potential ofthese birds (Havenstein et al., 2003), but other factors,such as breeders' age, levels of fed intake, and dietary composition of broiler breeders, may also influence the performance of offspring (Triyuwanta et al., 1992;

Li Jing-feng, Xu Liang-mei*, Zhang Yan-yun, Jiang Dan, Zhang Jing, Zhang Hui, and Li Jie

Institute of Animal Nutrition, Northeast Agricultural University, Harbin 150030, China

June 2014 Vol. 21 No. 2 46-52Journal of Northeast Agricultural University (English Edition) Available online at www.sciencedirect.com

ScienceDirect

E-mail: [email protected]

Lopez & Leeson, 1994; 1995; Hossain et al., 1998; Peebles et al., 1999a; 1999b). A series of reports fromEnting et al. (2007) showed that low energy broiler breeders' diets resulted in an increase in egg produc-tion and could affect embryonic development, and performance and mortality of their offspring. Spratt et al. (1987) reported that diet energy would influence20-day-old body weight of the male offspring. Mater-nal feed restriction could affect blood biochemical indices and hormone levels of embryo (Zhang et al., 2011) and fat deposition of offspring by changing the activity and mRNA expression levels of liver fatty acid synthase (Hu et al., 2010). However, few studies have approached to the effects of broiler breeder energy restriction on performance of offspring. The present study was conducted to investigate the effects of broiler breeder energy restriction on growth perfor-mance, fat deposition and serum indices of offspring.

Materials and Methods

Dietary treatments of broiler breedersThis experiment was conducted at the Experimental

Poultry Farm of Northeast Agricultural University. A total of 400 females Arbor Acres broiler breeders and 20 males at 20 weeks of the age were selected from the breeder stock. These female birds were divided into four treatments randomly (each treatment represented by five replicates of 20 birds), including three experi-mental treatments and one control. Treatment 1 was the control, in which normal energy density diets were fed during the experiment (ND, 11.70 MJ • kg-1 of ME). In the treatments 2, 3 and 4, the levels of energy decreased by 20%, 30% and 50% (LD20, LD30 and LD50), respectively.　The experimental period started when egg produc-tion reached 5%, and ended in week 45. Each bird was housed in the individual cage measuring 48 cm×34 cm×39 cm, with feed supply restricted and water fed ad litibum. The nutritional requirements of the female diets are shown in Table 1.　From 21 weeks old, the lighting program was started combining natural and artificial light. The lighting time was increased by 30 min per week from 14 h per day until reaching 16 h, and then maintained at 16 h per day thereafter.

Table 1　Composition and nutrient levels of experimental diets (air-dry basis) (g • kg-1)

Item ND1 LD201 ND301 ND501

IngredientCorn 620.4 480.0 379.8 180.0

Soybean meal 261.0 292.0 310.8 349.8Soybean oil 20.0

NaCl 1.7 1.7 1.7 1.7CaHPO4 15.0 16.0 16.5 18.0

Limestone 77.0 76.0 76.0 75.0Methionine 0.6 0.8 0.9 1.2

Choline chloride 1.0 1.0 1.0 1.0Premix2 3.3 3.3 3.3 3.3

Rice hull powder 129.2 210.0 370.0Total 1 000.0 1 000.0 1 000.0 1 000.0

Calculated value, dry matter (DM) basisME（MJ • kg-1） 11.70 9.36 8.19 5.85

CP (g • kg-1) 170.0 170.0 170.0 170.0Lysine (g • kg-1) 8.0 8.0 8.0 8.0

Methionine (g • kg-1) 3.4 3.4 3.4 3.4Ca (g • kg-1) 33.0 33.0 33.0 33.0

Available phosphorus (g • kg-1) 4.5 4.5 4.5 4.5

1 ND=Normal energy density; LD20=20% low energy density; LD30=30% low energy density; LD50=50% low energy density. 2 The premix provides the following per kg of diets: retinol 3.6 mg, cholecalciferol 0.06 mg, DL-α-tocopheryl acetate 30 mg, menadione sodium bisulphate 1.5 mg, cobalamin 0.012 mg, thiamine 2.0 mg, biotin 0.20 mg, folic acid 1.2 mg, nicotinic acid 35 mg, pantothenic acid 12 mg, pyridoxine 4.5 mg, riboflavin 9 mg, Cu (CuSO4 • 5H2O) 8 mg, I (KI) 1.0 mg, Fe (FeSO4 • 7H2O) 80 mg, Mn (MnSO4 • H2O) 100 mg, Se (Na2SeO3) 0.30 mg, and Zn (ZnO) 80 mg.

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·47·Li Jing-feng et al. Effects of Maternal Dietary Energy Restriction on Fat Deposition of Offspring

Dietary treatments of chicksBirds were fertilized at 40 weeks of the age. During 41 to 42 weeks of the age, 900 eggs were collected and then stored at 10℃ until incubation. Eggs were incubated at a constant eggshell temperature of 37.8℃ during the entire incubation period. After hatching, all male broiler chickens were selected and transported to the Experimental Poultry Farm of Northeast Agri-cultural University, China. Birds were reared under the same normal conditions in stair-step cages with five replicates per treatment according to broiler feeding schedule. In all the broiler chicken experiments, light was provided 23 h per day. The environmental temperature was maintained at 32-34℃ for the first week and then decreased gradually to 21℃ by 2-3℃ perweek and the room temperature was controlled at 18-24℃ thereafter. The whole experimental period lasted for 49 days. Birds were fed the same corn-soybean-based diets meeting or exceeding the nutrition standard of Chinese NY/T 33-2004 (1-3 weeks, ME 12.54 MJ • kg-1, CP 21.52%; 4-6, ME 12.96 MJ • kg-1, CP 19.98%; 7 weeks, ME 13.17 MJ • kg-1, CP 18.00%). Chickens had ad libitum access to water and feed during the trial.

Sample collectionOn days 28 and 49, the broiler offspring were fasted for 12 h and then the birds and feed were then weighed to determine the average daily gain (ADG), the average daily feed intake (ADFI), and the feed conversion ratio.　On days 28 and 49, two birds randomly from each replicate were selected and euthanized for sampling. Blood was collected (5 mL) by cardiac puncture into a 10-mL anticoagulant-free Vacu-tainer tube (Greiner Bio-One GmbH, Kremsmunster, Austria) and then centrifuged at 3 000×g for 10 min to obtain serum. The serum samples were stored at −20℃ until analyses. Abdominal fat and fat tissues surrounding the proventriculus and gizzard lying against the inside abdominal wall and around the cloaca, was collected as described by Ain Baziz et al (1996). Subcutaneous fat

thickness and intermuscular fat width were measuredby vernier caliper according to Ricard et al. (1983) and Baziz et al (1983). At last, liver and right breast muscle were removed and stored for further analyses. The fat content of liver and breast muscle were determined by Soxhlet extractor method (Zhang, 2003).　The serum indices, including the total cholesterol (C), triglyceride (TG), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) were assayed by an automatic biochemical analyzer (RA-1000, Bayer Corp., Tarrytown, NY.) with commercial reagent kits(Zhongsheng Beikong Bio-Technology and Science, Inc. Beijing, China). The serum triiodothyronine (T3) and thyroxine (T4) were measured by radioi-mmunoassay kit (Diagnostic Systems Laboratories Inc., Webster, TX).

Statistical analysisData was analyzed by ANOVA by using GLM pro-cedure of SAS institute (2000). Duncan's multiple range test and critical difference were determined at 5% significance level. The results of statistical analyses were shown as means±standard deviation.

Results

The 1-day-old chicken weight reduced in offspring from breeders fed low energy diets (Table 2), compar-ing with the control diet. No significant difference was found on 28-day-old chicken weight. Compared with the control, 49-day-old body weight in offspring from breeders fed LD20 diets increased (P<0.05). ADFI and ADG in offspring were not significantly affected during days 1-28, and offspring from breeders fed LD50 diet markedly exhibited an increasing ADFI during days 1-49 (P<0.05). ADG in offspring from breeders fed LD20 diet was higher compared with those from breeders fed ND (P<0.05). Feed conversion ratio of offspring from broiler breeders fed LD50 diet significantly decreased during the experimental period (days 1-49) as compared with that of the control (P<0.05).


Journal of Northeast Agricultural University (English Edition)·48· Vol. 21　No. 2　2014

Experimental day Serum biochemical indice ND LD20 LD30 LD50

28

C (mmol • L-1) 3.51±0.37 3.36±0.47 3.03±0.31 3.06±0.45

TG (ng • mL-1) 0.96±0.12ab 0.87±0.05b 0.89±0.09b 1.05±0.12a

LDL (mmol • L-1) 2.00±0.15 1.93±0.13 1.83±0.26 1.87±0.16

HDL (mmol • L-1) 0.94±0.13 1.05±0.15 1.05±0.13 1.03±0.10

T3 (ng • mL-1) 1.68±0.13 1.59±0.06 1.48±0.15 1.78±0.18

T4 (ng • mL-1) 72.46±7.09ab 62.33±2.79b 59.50±2.55b 78.22±10.56a

49

C (mmol/L) 2.75±0.27a 2.34±0.10b 2.93±0.28a 2.82±0.35a

TG (ng • mL-1) 0.78±0.05 0.81±0.08 0.82±0.07 0.84±0.11

LDL (mmol • L-1) 2.00±0.15 1.93±0.13 1.83±0.26 1.87±0.16

HDL (mmol • L-1) 0.91±0.12a 0.90±0.08a 0.86±0.10ab 0.79±0.11b

T3 (ng • mL-1) 1.97±0.04b 2.58±0.26a 2.44±0.18a 2.21±0.24ab

T4 (ng • mL-1) 81.58±2.85a 64.28±3.25b 57.33±2.95bc 56.12±3.39c

Experimental day Item ND LD20 LD30 LD50

1

BW (g)

48.78±1.59a 45.72±0.71b 43.27±0.70c 41.81±0.97d

28 1 266.00±111.00 1 205.00±207.00 1 184.00±137.00 1 227.00±176.00

49 2 980.00±126.00b 3 253.00±208.00a 3 083.00±182.00ab 2 899.00±144.00b

1-28

ADFI (g) 66.06±2.84 65.37±2.67 65.35±2.59 65.93±2.89

ADG (g) 43.47±3.95 41.33±7.40 40.60±4.89 42.29±6.26

FC 1.52±0.05 1.58±0.10 1.61±0.14 1.56±0.18

1-49

ADFI (g) 107.76±3.89b 114.08±3.14ab 114.73±2.11ab 119.38±2.80a

ADG (g) 58.57±7.10b 65.45±7.21a 61.97±5.02ab 58.28±6.49b

FC 1.84±0.06b 1.74±0.13b 1.85±0.10b 2.03±0.13a

　Dietary treatments on serum indices of offspring are presented in Table 3. On 28 days of the age, both serum TG and T4 levels in offspring of breeders fed LD50 diet were higher than those from breeders fed LD20 and LD30 diets (P<0.05), whereas no differences were observed in comparison with ND. There wasno difference in C, T3, LDL, and HDL levels in offsp-ring among treatments, and the same result was obtained on 49-day-old serum TG and LDL levels.

On 49 days of the age, serum C level in offspring of breeders fed LD20 diet and serum HDL level in offspring from breeders received LD50 diet were lower than those in offspring from broiler breeders given ND (P<0.05). In addition, a higher T3 content in serum was found in the offspring of breeder fed LD20 and LD30 diets (P<0.05). Serum T4 level in offspring significantly decreased with the decreasing of breeder energy in diets (P<0.05).

Table 2　Effects of maternal dietary energy restriction on growth performance of offspring

a, b, and c mean letters in the same row are significantly different (P<0.05). The same as below.

Table 3　Effects of maternal dietary energy restriction on serum indices of offspring

　Effects of maternal energy restriction on fat deposi-tion of offspring are shown in Table 4. The difference

in intermuscular fat width among treatments was not found on days 28 and 49. Compared with ND, the



Experimental day Fat deposition ND LD20 LD30 LD50

28

Fat content of breast muscle 5.65±0.23c 6.10±0.61b 7.01±0.49a 7.40±0.39a

Liver fat percentage 14.30±2.44c 16.89±2.88ab 14.91±1.57bc 17.32±3.31a

Abdominal fat percentage 1.17±0.06 1.16±0.06 1.18±0.05 1.20±0.08

Subcutaneous fat thickness (cm) 0.72±0.08b 0.73±0.04ab 0.75±0.09ab 0.82±0.06a

Intermuscular fat width (cm) 0.93±0.03 0.91±0.04 0.93±0.06 0.95±0.10

49

Fat content of breast muscle 3.10±0.24b 3.26±0.38b 3.02±0.28b 3.67±0.38a

Liver fat percentage 17.36±1.05 18.25±0.77 18.19±0.46 18.35±0.51

Abdominal fat percentage 1.55±0.19b 1.65±0.16ab 1.76±0.20a 1.60±0.11ab

Subcutaneous fat thickness (cm) 0.91±0.11b 0.94±0.10ab 1.04±0.08a 0.95±0.05ab

Intermuscular fat width (cm) 1.11±0.02 1.12±0.02 1.15±0.07 1.16±0.11

abdominal fat percentage did not differ in offspring of 28-day-old; however, it had a significant increase in 49-day-old offspring of breeders fed LD30 diet (P<0.05). On 28 days of the age, the fat content of breast muscle was higher in experimental treatments (P<0.05); whereas, only offspring from breeders given LD50 diet was higher on 49-day-old (P<0.05). In offspring from broiler breeders fed LD20 and LD50

diets, liver fat percentage was higher on day 28 than that fed ND (P<0.05), but no difference was found on day 49 among treatments. On 28 days of the age, there was an increasing trend in subcutaneous fat thickness in offspring. In addition, on 49 days of the age, the subcutaneous fat thickness in offspring was significantly improved from LD30 diet as compared with that in the control (P<0.05).

Table 4　Effects of maternal energy restriction on fat deposition of offspring

Discussion

The results of this experiment showed that maternal energy restriction affected the performance of their offspring. 　Our results showed that low energy diets would decrease 1-day-old body weight in offspring of breeders, which was in accordance with the findings of Xu et al. (2010) that broiler offspring tended to have a lower 1-day-old body weight from broiler breeders fed low energy diets. However, the offspring were able to compensate for changes when normal postnatal nutrition was given. A higher 49-day-old body weight was found in offspring from breeders given LD20 diet; however, no significant difference was found for low energy diets. ADG in offspring of breeders fed LD20 diet and ADFI and feed conversion ratio of offspring from breeders given LD50 diet were higher during

days from 1 to 49, these results were consistent with the findings of Enting et al. (2007) that ADFI was higher in offspring from broiler breeders fed limited feed. Triyuwanta et al. (1992) found that the effects of maternal diets tended to disappear as offspring age increased.　C, TG, HDL and LDL are important indices of lipid metabolism. The fat deposition of poultry relays on TG contention in blood. LDL, the major carriers of cholesterol, can take cholesterol to liver. And serum HDL represents the clearing situation of C, which can combine the redundant blood lipids and take it out of the body (Triyuwanta et al., 1992; Xu et al., 2010). Our results showed that the offspring from breeders fed LD20 diet had a much lower content of C and those from LD50 group had a lower content of HDL in serum on day 49 than those from ND group. These results were against the findings of Li et al. (2010) that C increased in lean line 28-day-old offspring from



broiler breeders fed less feed during laying period. The contradictory results of the two studies might come from different hen breeder strains and ages, dietary treatment feed, management protocols, and environmental factors. Taken together, the present results suggested that offspring from breeders given LD20 and LD50 diets had a much more robust lipid metabolism. 　Maternal nutrition may alter the nutrient supply to the fetus and thereby affect the fetal production of essential growth regulatory factors in the blood and tissues, which may in turn modify nutrient availability to the fetus (Rehfeldt et al., 2004). Thyroid hormone as an important regulator in the growth and fat metabolism of poultry could promote the transformation and the decomposition of fat, and most T4 act as taking off the iodine to T3 in peripheral tissue (Smith and Freund, 2002). In this study, the contention of T3 significantly increased in offspring from breeders received LD20 and LD30 diets. These results were consistent with the findings of Li et al. (2010) that T4 and T3 contents were respectively lower and higher for lean line hens fed limited food.　Previous studies suggested that low protein intake of pregnant rodents had a permanent effect on the growth capacity of their offspring (Strakovsky et al., 2010).In our study, the percentage of abdominal fat and liver fat, fat content of the breast muscle and subcutaneous fat thickness increased in offspring when low energy diets were given to broiler breeders. These results were consistent with Fontana et al. (1992) that the abdominal fat increased when the broiler recovered to ad libitum after feeding restriction. These results were also consistent with the findings of Anguita et al.(1993) that the offspring tended to deposit large amounts of fat in later growth process when maternal was fed limited food during pregnancy. The possible reason may be long time energy restriction affecting the expression of children growth regulatory factors in body and the nutrient efficiency, and then increasing the body fat deposition of their offspring by altering the nutrition deposition in eggs (Lippens et al., 2000).

Conclusions

In conclusion, with a lower 1-day-old weight, the offspring showed a better growth performance and a promoted lipid metabolism for broiler breeders fed low energy diets. The offspring of broiler breeders fed LD20 had the optimum performance.

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