Fat Deposition In Broilers Research Articles

In ovotemperature manipulation differentially influences limb musculoskeletal development in two lines of chick embryos selected for divergent growth rates

Selective breeding has led to diverging phenotypic evolution in layer and broiler chickens through genomic and epigenetic modifications. Here we show that in ovo environmental manipulation differentially influences embryonic limb muscle phenotype in these two breeds. We demonstrate that raising incubation temperature from 37.5 to 38.5°C between embryonic days (ED) 4 and 7 increased motility and body mass in both layer and broiler embryos. In layers, this was accompanied by gastrocnemius muscle hypertrophy, increased fibre and nuclei numbers and a higher nuclei to fibre ratio (ED18), preceded by increased hindlimb Myf5 (ED5-8), Pax7 (ED5-10), BMP4 (ED6-9) and IGF-I (ED9-10, ED18) mRNAs. In broilers, the same temperature treatment led to reduced gastrocnemius cross-sectional area with fewer fibres and nuclei and an unchanged fibre to nuclei ratio (ED18). This was preceded by a delay in the peak of hindlimb Myf5 expression, increased Pax7 (ED5, ED7-10) and BMP4 (ED6-8) but reduced IGF-I (ED8-10) mRNAs. Rather than promoting myogenesis as in layer embryos, the temperature treatment promoted gastrocnemius intramuscular fat deposition in broilers (ED18) preceded by increased hindlimb PPARγ mRNA (ED7-10). The treatment increased tibia/tarsus bone length as well as femur cross-sectional area in both breeds, but femur length and bone to cartilage ratio in the femur and tibia/tarsus were only increased in treated layers (ED18). We conclude that in ovo temperature manipulation differentially affected the molecular regulation of hindlimb myogenic, adipogenic and growth factor expression in broiler and layer embryos, leading to differential changes in muscle phenotype. The underlying interactive mechanisms between genes and the environment need further investigation.

Expression profiling of candidate genes for abdominal fat mass in domestic chicken Gallus gallus

The quantitative traits of mass and percentage of abdominal fat in chicken and various types of obesity in mammals are homologous and functionally similar. Therefore, the genes involved in obesity development in humans and laboratory rodents as well as those responsible for pig lard thickness could be involved in abdominal fat deposition in broilers. Expression of candidate genes FABP1, FABP2, FABP3, HMGA1, MC4R, PPARG, PPARGC1A, POMC and PTPN1 was studied in fat, liver, colon, muscle, hypophysis, and brain in chicken (broilers) using real-time PCR. Significant difference in the HMGA1 gene expression in the liver of broiler chicken with high (3.5 +/- 0.18%) and low (1.9 +/- 0.56%) abdominal fat concentration has been revealed. The expression of this gene was been shown to correlate with the amount (0.7, P < or = 0.01) and mass (0.7, P < or = 0.01) of abdominal fat. The PPARG gene expression in liver in the same chicken subsets was also significantly different. Correlation coefficients of the gene expression with the abdominal fat amount and mass were respectively 0.55 (P < or = 0.05) and 0.57 (P < or = 0.01). Based on these results, we suggest that the HMGA1 and PPARG genes are involved in abdominal fat deposition. The search for single nucleotide polymorphisms (SNPs) in the HMGA and PPARG regulatory regions could facilitate identifying genetic markers for broiler breeding according to the mass and percentage of abdominal fat.

Nutritive value of poultry meat: relationship between vitamin E and PUFA

Fat content in poultry meat is relatively low (2.8 g/100 g breast and 13 g/100g thigh) and with a positive unsaturated/saturated fatty acid ratio, from a human health point of view. It is well established that we can modify lipid fraction through dietary strategies in order to improve nutritive value. When the dietary polyunsaturated fatty acid (PUFA) level increases, the PUFA content in the chicken tissues also increases. But this enrichment in PUFA, especially in omega-3, leads to a higher number of double bonds in the meat and this provokes different consequences. The use of dietary PUFA fat causes a decrease in the body fat deposition in broilers. Furthermore, an increase in the degree of PUFA in meat enhances the development of organoleptic problems and increases the susceptibility to oxidation. Since antioxidants, especially vitamin E, protect PUFA from oxidation damage, its inclusion in chicken diets must be assured. Alpha-Tocopherol (alpha-Toc) content in poultry meat increases linearly as the dietary alpha-Toc supplementation increases, but it is affected by the PUFA content. As the dietary PUFA level increases, the alpha-Toc content of chicken meat decreases. To achieve the same tissue alpha-Toc concentration, the vitamin E requirements increase by 2.5 and 3.7 mg per each g of dietary PUFA. The potential healthy beneficial effect of PUFA enriched meat will be limited if the antioxidant content, such as vitamin E, which prevents oxidation, is not assured. The dietary supplementation with alpha-Toc and PUFA should be adjusted depending on our aims: nutrient enrichment and/or lipid oxidation minimization.

Turmeric (Curcuma longa) Root Powder and Mannanoligosaccharides as Alternatives to Antibiotics in Broiler Chicken Diets

Two bio-assays were conducted to evaluate turmeric root powder and mannan-oligosaccharides (MOS) as alternatives to feed antibiotics for broilers. In one trial, one hundred and eighty 19-days old broilers assigned to 18 groups of 10 were fed on one of six experimental diets with three replicates during four weeks. The diets included a basal feed without additives and with either virginiamycin, MOS, or turmeric at 1, 2 and 3 g/kg, respectively. In the second trial, one hundred and forty four 21-days old broilers arranged in 16 groups of nine were fed on the first four diets with four replicates for a similar period. Virginiamycin, MOS and turmeric (1 g/kg) in the first trial generally improved the weight gain of broilers by 3.4, 6.2 and 5.3%, respectively. In the second trial they increased the weight gain significantly (p<0.05) by 8.8, 8.0 and 15.1%, respectively. Additives improved the feed efficiency up to 15.1% and carcass recovery up to 3.1% (p<0.05). Virginiamycin, MOS and turmeric (1 g/kg) markedly reduced the abdominal fat content from 1.91% BW in the control to 1.44, 0.97 and 1.2% BW, respectively, in the first trial. The corresponding values obtained in the second trial were 1.01, 0.55 and 0.6%, respectively as compared to 1.22% in the control group. All additives showed a remarkable inhibition of duodenal coliform bacteria, yeast and mould in the caecum, and all viable microbes in the ileum. A significant (p<0.05) improvement in energy and protein utilization could be recorded with supplemented diets except for high turmeric diets. Dietary 2 and 3 g/kg addition of turmeric reduced energy and protein utilization as well as fat deposition. Present results reveal that turmeric and MOS are satisfactory alternatives to antibiotics in broiler feeds. Both MOS and turmeric possess an antimicrobial effect in vivo. Turmeric may also depress fat deposition in broilers. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 10 : 1495-1500)

Dietary linseed oil produces lower abdominal fat deposition but higher de novo fatty acid synthesis in broiler chickens

Previous experiments have shown lower abdominal and body fat deposition in broilers fed polyunsaturated fatty acids (PUFA) compared with those fed saturated fatty acids (SFA) or monounsaturated fatty acids (MUFA). These changes in fat deposition may be related to different rates of lipid synthesis or lipid oxidation. In Experiment 1, in vivo lipogenesis of broilers fed different dietary fatty acid profiles (tallow, sunflower oil, or linseed oil) was investigated. In Experiment 2, liver fatty acid deposition of broilers fed a basal diet (without additional fat) or diets with added tallow, olive oil, sunflower oil, or linseed oil was studied. Results from Experiment 1 showed higher rates of de novo fatty acid synthesis in broilers fed the diet with added linseed oil (P < 0.05), compared with those fed tallow or sunflower oil. In Experiment 2, values of liver-to-dietary-fatty-acid ratios of fatty acids from endogenous synthesis (SFA, n-7 and n-9 fatty acids) were higher in broilers fed linseed oil and the basal diet. Results obtained in both experiments suggest that lower abdominal and body fat deposition of broilers fed PUFA compared with those fed SFA or monounsaturated fatty acids is mainly due to differences in lipid oxidation rates and that the higher in vivo lipogenesis found in broilers fed linseed oil would be another mechanism to dissipate energy, contributing to the lower fat deposition in these birds.

Dietary fatty acid profile modifies abdominal fat deposition in broiler chickens

An experiment was conducted to study the effect of different dietary fatty acid profiles on abdominal fat deposition in broilers. Diets with four types of fats (tallow, olive oil, sunflower oil, and linseed oil), at two levels of fat inclusion (either 6 or 10%), were administered to males from 21 to 42 d and to females from 21 to 49 d of age. The sexes were studied separately. Performance parameters, abdominal fat, muscle fat and cholesterol, and fatty acid profile of thigh, breast, and abdominal fat were determined. Broilers fed sunflower and linseed oils presented better values of feed efficiency. Abdominal fat and cholesterol content of thigh muscle were significantly lower in animals fed sunflower and linseed oils than in those fed tallow or olive oil (P < 0.001). In females, abdominal fat increased with level of fat inclusion only in birds fed tallow or olive oil, whereas it remained constant in birds fed sunflower or linseed oil. Muscle fat content was lower for birds fed tallow or olive oil but not significantly. The fatty acid profile of the different tissues reflected dietary fatty acid profile. Monounsaturated fatty acids were higher in abdominal fat, whereas polyunsaturated fatty acids were higher in muscle fat. These results suggest that polyunsaturated fatty acids produce lower abdominal fat deposition than saturated or monounsaturated fatty acids.

Effects of early feed restriction on the performance of broilers

An experiment was conducted to compare the effects of early feed restriction on the performace and abdominal fat deposition in broilers. The treatments consisted of providing feed ad libitum (Full-fed) and three feed restriction treatments of restricting feeding between 8-21 days of age (DOA) either for a duration of 7 days or 14 days. The three feed restriction treatments were Restrict 8-14 DOA, Restrict 8-21 DOA and Restrict 15-21 DOA. Liveweights and feed consumption were obtained at weekly intervals. Samples of both male and female broilers broilers were taken at 43 DOA to determine the weight of abdominal fat, liver and gizzards. Feed efficiency was generally improved by feed restriction, but a compensatory gain was not observed in the restricted groups. Broilers on restricted feeding also had lower mortality as compared to the full-fed broilers. There is no effect of early feed restriction on the weight of the abdominal fat and the dressing percentages but the weights of the liver and gizzard were affected by restriction. Also there was an effect of sex on the weights of the abdominal fat, the liver and gizzard of the males and females.

Dietary Addition of Cellular Metabolic Intermediates and Carcass Fat Deposition in Broilers

Ninety-six 1-day-old male broilers were fed a diet containing 0, 2, 4, 6, 8, or 10% of a 1:1 mixture of pyruvic acid (PY) and dihydroxyacetone (DH) for ad libitum consumption for 42 days. Feed intake, body weight gain, and feed efficiency decreased linearly (P < .001) with increasing levels of PY and DH. There were no significant differences among treatments for abdominal fat percentage. Carcass chemical analysis revealed small but significant (P < .05) differences among dietary treatments for protein and fat percentages. In a second experiment, 1921-day-old male broilers were fed diets containing 5% of PY, lactic acid (LA), citric acid (CI), DH, or glycerol (GY) or mixtures (1:1) of DH or GY in combination with each organic acid. Bird performance was impaired (P < .05) by PY or CI but not by DH or GY. Lactic acid reduced (P < .05) feed intake by 9% without affecting weight gain. Lactic acid plus DH, CI plus DH, and CI plus GY mixtures decreased (P < .05) bird performance but other combinations had no effect. Pyruvic acid or CI decreased abdominal fat and carcass lipid percentages. Dihydroxyacetone increased (P < .05) carcass lipid percentage and GY increased (P < .05) abdominal fat percentage. Lactic acid plus DH increased (P < .05) carcass lipid percentage. Only PY and CI decreased carcass fat deposition, but they also impaired broiler performance.

Effect of different dietary levels of protein on fat deposition in broilers divergently selected for high or low abdominal adipose tissue.

1. Male broilers selected for high (HF) or low (LF) abdominal fat were fed from 8 to 53 d of age on diets containing different concentrations of protein: according to N.R.C. (1984) recommendations (IP), 14% lower (LP) or 14% higher (HP). 2. The growth of LF birds fed on the LP diet was depressed until 35 d of age, but did not differ from the other groups later on. 3. The HF birds had heavier adipose tissues (AT) (g/kg body weight) than the LF birds. Significant line by diet interactions indicated a difference in magnitude of the response of the lines to dietary protein content. 4. Fat concentration of the AT and skin was higher, and in the tibia lower in the HF than in the LF birds. The fat concentration in liver and in breast muscle was not affected by line or by diet. 5. The ratio of saturated plus monoenoic fatty acids to polyenoic fatty acids, considered as an index of fat synthesis, was higher in the abdominal adipose tissue (AAT) of HF compared with LF birds. In AAT, liver and in breast muscle, this ratio was inversely related to dietary protein content.

Why are young broiler chickens fatter than layer-strain chicks?

1. 1. The abdominal fat pads of 5 week-old broiler and layer chicks incorporated 6.0 and 3.9% of intravenously-injected 14C-labelled very low density lipoproteins respectively. 2. 2. These proportions of total plasma lipoprotein flux were sufficient to account for about 65–70% of the rate of fat deposition in broilers, but were more than 4-fold greater than that the rate of fat deposition in layers. 3. 3. [ 14C]Palmitate taken up into adipose tissue of layer chicks had a t 1 4 of 2–3 days. 4. 4. There was no significant turnover of adipose tissue triglycerides in broilers and this appears to be a major reason for their relative fatness.

Effect of dietary concentrations of fat and energy on fat deposition in broilers divergently selected for high or low abdominal adipose tissue∗

1. Fat deposition in abdominal, mesenterial, sartorial and gizzard adipose tissues (AT), liver, breast muscle, skin and carcase was studied in male broilers, selected for high (HF) and low (LF) abdominal fat and fed on diets differing in energy density and total fat content. 2. There were no significant differences in body weight in the experimental groups. The relative weight (g/kg body weight) of the dissected adipose tissues was higher in HF than in LF birds. Fat concentration in the AT (sartorial excepted), skin and body was higher in the HF compared with the LF birds. The lines did not differ significantly in liver and breast muscle fat content. 3. Abdominal AT was affected by selection or dietary fat more than other AT and total body fat. 4. In the HF birds increasing energy density from 12.3 to 13.4 MJ/kg (dietary fat kept constant: 5.46 g/MJ) significantly increased the weight of the abdominal, mesenterial and sartorial AT. Increasing dietary fat (at both energy densities) decreased the weight of the AT, whereas increasing both energy and fat did not affect it. In the LF birds, similar but milder and insignificant trends were observed. It is suggested that this interaction has biological significance.

Effect of Differing Light Intensities on Abdominal Fat Deposition in Broilers

Two trials were conducted in an attempt to determine if light intensity affected fat content of broilers as measured by the amount of abdominal fat. The light regimens used from 10 days of age had constant intensities of 2 or 52 lx. Results obtained showed that light intensity did not significantly influence the amount of abdominal fat produced by males or females at either 49 or 63 days of age. Light intensity had no significant effect on body weight, feed conversion (grams feed per gram body weight), or mortality at either 48 or 62 days of age for broilers of the same sex. The amount of light used was the amount produced from either 7.5 or 75-W incandescent bulbs in an enclosed house that was 11 m wide with two strings of light bulbs 2.1 m high on 3-m centers equidistant from the ends and sidewalls of the house.

Feather Meal as a Nonspecific Nitrogen Source for Abdominal Fat Reduction in Broilers During the Finishing Period

Earlier studies have shown that excessive abdominal fat deposition in broilers can be overcome by feeding feather meal (FM) during the finishing period (7 or 14 days prior to slaughter). Studies were conducted to determine if the observed fat reduction in FM-fed birds was due to factors other than supplying excess protein.The FM was added at levels of 4, 6, and 8% and glycine at levels of .125, .25, and .5%, similar to amounts contributed by corresponding levels of FM. Corn-soybean diets were also formulated at protein levels corresponding to those of FM diets. All experimental diets were fed from 35 to 49 or from 42 to 49 days of age.There were no significant differences in weight gain and feed efficiency of treatment and control groups during the study. The addition of glycine resulted in a significant (P<.05) reduction in abdominal fat content and appeared to be partially responsible for the observed reduction in FM-fed birds. Increasing the dietary protein level also significantly (P<.05) reduced abdominal fat deposition regardless of protein source. The study indicates that lower quality protein sources such as FM can be effectively used as a nonspecific nitrogen source for reducing abdominal fat deposition during the finishing period.

Reduction in Abdominal Fat Content of Broiler Chickens by the Addition of Feather Meal to Finisher Diets

Two trials were conducted to evaluate the effectiveness of feather meal (FM) as a protein source for reducing abdominal fat in broilers during the finishing period (35 to 49 days of age). Birds were grown to 35 days of age on diets that met the National Research Council (NRC, 1984) nutrient recommendations and then assigned to one of the test diets.In the first trial, FM was added to the diets at 0, 2, 4, or 6%, assuming 100, 50, or 0% amino acid availability (based on the NRC amino acid values for FM). Addition of FM resulted in an increase in dietary protein content. Sample birds were processed at 49 days of age to determine abdominal fat content and dressing percentage. Addition of FM resulted in a significant (P<.05) reduction in abdominal fat regardless of assumed amino acid availability. There were no significant differences in rate of gain, feed efficiency, and dressing percentage.In Trial 2, test diets were fed either from 35 to 49 days of age with 0, 2, 4, 6, or 8% FM or from 42 to 49 days of age with 0, 2, 4, 6, 8, or 10% FM. All diets were formulated assuming 50% amino acid availability. A significant (P<.05) reduction in abdominal fat was again observed in birds fed FM except at the 2% FM level. No significant differences occurred in body weight, efficiency of food utilization, and dressing percentage. These data indicate that short-term feeding of FM may aid in reducing abdominal fat deposition in broilers. This reduction is probably due to the increased dietary protein content associated with FM addition, but the possibility that certain nonessential amino acids present in FM contribute to the reduction cannot be totally ruled out.

Abdominal Fat Pad Reduction in Broilers with Thyroactive Iodinated Casein

Two experiments were conducted to determine the effectiveness of thyroactive iodinated casein (Protamone) in preventing excessive fat deposition in broilers and to determine the most practical level of protamone when considering growth, fat deposition, feed efficiency, and other characteristics. In Experiment 1, 128 commercial broiler chicks (Cobb Color Sex) were fed diets containing each of the following protamone levels: 0, 55, 100, 200, 500, and 1500 mg/kg. Based on the results of Experiment 1, the levels used in Trial 2 were: 0, 100, 200, and 400 mg protamone/kg feed. All birds were processed at 49 or 51 days of age in Experiment 1 and at 49 days in Experiment 2. A protamone level of 100 mg/kg decreased fat deposition without decreasing body weight. Higher levels caused further reductions in fat deposition but with some loss of body weight. Feathering at 2 weeks of age and water pickup during chilling were also improved by protamone. Protamone feeding also resulted in poorer feed conversion, greater shrink and dressing losses, and at the highest levels, increased mortality, lower carcass grade, and lower conformation scores. Protamone fed at low levels appears to have potential as a tool in reducing excess fat in broilers.

Nutritional Factors Influencing Carcase Fat in Broilers—A Review

SummaryExcessive fat deposition in broilers, which reduces the profit margin for poultry processors and makes effluent disposal difficult, responds to dietary manipulation.When the energy consumed by the bird exceeds that required for maintenance and growth, the remainder is deposited as fat. It is the ratio of energy to good quality protein in broiler diets rather than the energy level per se, that influences carcase fat deposition. Furthermore, the effect of a given energy to protein ratio is independent of the source of the energy.The addition of specific amino acids in order to improve the amino acid balance of the diet affects fat deposition, as does the inclusion of excessive amounts of individual amino acids or a low quality protein.The composition of carcase fat is an important factor in determining processing loss, product quality and shelf life. A carcase with relatively unsaturated fat tends to be greasier, more susceptible to oxidation and contributes more fat to processing effluent than a more saturated carcase. The composition of carcase fat depends upon the degree of hepatic lipogenesis and the nature of the dietary fat.

Relationship between Increased Body Weight and Fat Deposition in Broilers

Selection for increased body weight or growth rate could result in increased fat deposition rather than protein deposits for the following reasons: (1) The animal has little, if any, capability to ...

Fat Deposition in Broilers: Effect of Dietary Energy to Protein Balance, and Early Life Caloric Restriction on Productive Performance and Abdominal Fat Pad Size

The effect of dietary energy to protein balance, and early life caloric restriction on abdominal fat pad development in the male broiler chicken was studied. Dietary energy concentration had no significant (P ≤ 0.05) effect on abdominal fat pad size, although decreasing the calorie.protein ratio of the diet resulted in a significant (P ≤ 0.05) reduction in the proportion of this tissue in the body. Reducing the calorie: protein ratio from a level considered optimum, by the addition of feather meal to the diet was equally as effective in reducing fat pad size as was the addition of a higher quality protein as exemplified by soybean meal plus dl-methione. Restricting the caloric intake of broilers in the 0–3 week growing period by the use of an ad libitum fed low energy diet (2233 kcal. M.E./kg.) had no significant (P ≤ 0.05) effect on fat pad development. It is suggested that the degree of calorie restriction was not of sufficient magnitude to influence adipocyte hyperplasia. These results are discussed in relation to findings with other avian and mammalian species.

Fat Accretion during Postembryonic Growth in the Domestic Duck, with Additional Data from the Mallard

Previous articleNext article No AccessFat Accretion during Postembryonic Growth in the Domestic Duck, with Additional Data from the MallardA. J. EvansA. J. Evans Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Volume 45, Number 2Apr., 1972 Article DOIhttps://doi.org/10.1086/physzool.45.2.30155580 Views: 2Total views on this site Citations: 10Citations are reported from Crossref Journal History This article was published in Physiological Zoology (1928-1998), which is continued by Physiological and Biochemical Zoology (1999-present). PDF download Crossref reports the following articles citing this article:Greta Geldenhuys, Louwrens C. Hoffman, Nina Muller Aspects of the nutritional value of cooked Egyptian goose (Alopochen aegyptiacus) meat compared with other well-known fowl species, Poultry Science 92, no.1111 (Nov 2013): 3050–3059.https://doi.org/10.3382/ps.2013-03342Fang Ding, Zhixiong Pan, Jie Kou, Le Li, Lu Xia, Shenqiang Hu, Hehe Liu, Jiwen Wang De novo lipogenesis in the liver and adipose tissues of ducks during early growth stages after hatching, Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 163, no.11 (Sep 2012): 154–160.https://doi.org/10.1016/j.cbpb.2012.05.014D.C. CUNNINGHAM, W.D. MORRISON Dietary Energy and Fat Content as Factors in the Nutrition of Developing Egg Strain Pullets and Young Hens, Poultry Science 56, no.66 (Nov 1977): 1792–1805.https://doi.org/10.3382/ps.0561792Margaret W. Stanier Effect of environmental temperature and food intake on the distribution of fat in growing hairless mice, British Journal of Nutrition 37, no.22 (Aug 2007): 279–284.https://doi.org/10.1079/BJN19770029L. Griffiths, S. Leeson, J.D. Summers Fat Deposition in Broilers: Effect of Dietary Energy to Protein Balance, and Early Life Caloric Restriction on Productive Performance and Abdominal Fat Pad Size, Poultry Science 56, no.22 (Mar 1977): 638–646.https://doi.org/10.3382/ps.0560638F.E. Pfaff, J.D. Benson, R.E. Austic Influence of diet on adiposal lipoprotein lipase and hepatic triacylglyceride synthetase activities in the developing pullet (Gallus domesticus), Comparative Biochemistry and Physiology Part B: Comparative Biochemistry 58, no.44 (Jan 1977): 345–348.https://doi.org/10.1016/0305-0491(77)90179-1D.C. Cunningham, W.D. Morrison Dietary Energy and Fat Content as Factors in the Nutrition of Developing Egg Strain Pullets and Young Hens, Poultry Science 55, no.11 (Jan 1976): 85–97.https://doi.org/10.3382/ps.0550085A. J. Evans In vitro lipogenesis in the liver and adipose tissues of the female Aylesbury duck at different ages, British Poultry Science 13, no.66 (Nov 2007): 595–602.https://doi.org/10.1080/00071667208415986A. J. Evans Changes in adipocyte size during post‐embryonic growth in the female Aylesbury duck, British Poultry Science 13, no.66 (Nov 2007): 615–618.https://doi.org/10.1080/00071667208415989A.J. Evans Lipoprotein lipase activity in adipose tissues of the domestic duck: The effect of age, sex, and nutritional state, International Journal of Biochemistry 3, no.1414 (Apr 1972): 199–206.https://doi.org/10.1016/0020-711X(72)90080-8