Effects of dietary lipids and Clostridium butyricum on chicken volatile flavour compounds

Transcription

1 Indian J. Anim. Res., 52(8) 2018: Print ISSN: / Online ISSN: AGRICULTURAL RESEARCH COMMUNICATION CENTRE Effects of dietary lipids and Clostridium butyricum on chicken volatile flavour compounds Xuan Liu 1, Shurong Li 1, Zongyi Wang 2 and Bingkun Zhang 1 * State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Key Laboratory of Feed Safety and Bioavailability, Ministry of Agriculture, Beijing, P.R. China. Received: Accepted: DOI: /ijar.v0iOF.6998 ABSTRACT The effect of dietary lipids and Clostridium butyricum supplementation on chicken volatile aroma compounds was investigated. One hundred and ninety two one-day-old broilers were divided into 4 treatment groups in a 2x2 factorial arrangement, and fed four diets with two lipid sources (soybean oil or fish oil) and two levels of C. butyricum (0 or 1x10 9 CFU/Kg) for a period of 42 days. Dietary lipids and C. butyricum had no effect on broiler performance. The contents of C18:2, C18:3, C20:5n-3, C22:6n-3 and n-3 PUFA were significantly increased in breast muscle by feeding fish oil. Dietary oil had an effect on aroma compounds significantly in breast muscle. Cooked chicken breast muscle from fish oil diet had lower flavor, and the flavor was improved after supplementing with C. butyricum in the diet. The results of this study indicated that fish oil diets could increase the n-3 PUFA content of chicken meat, but lower flavor of cooked chicken. The lowered flavor could be improved by supplementing with C. butyricum in the diet. Key words: Broiler chicken, Clostridium butyricum, Fish oil, Soybean oil, Volatile aroma compounds. Abbreviations: PUFA: polyunsaturated fatty acid, SO: soybean oil without C. butyricum supplementation, FO: fish oil without C. butyricum supplementation, SCB: soybean oil with C. butyricum supplementation, FCB: fish oil with C. butyricum supplementation. INTRODUCTION With the continuous improvement of living standards in China, consumers demand safer food products with increased nutritional value and good meat flavor. One of the ways food scientists hope to accomplish this goal is by changing lipid content and fatty acid composition of foods. There is evidence that n-3 polyunsaturated fatty acid (PUFA) can protect against breast, colon, and prostate cancer (Rose and Connolly, 1999). It is reported that improvement of n-3 fatty acids in poultry meat can be achieved by increasing the levels of n-3 PUFA in poultry diets (Hulan et al., 1988), such as by supplementing fish oil in diet. Lipids are one of the major precursors of meat flavor (Mottram, 1998). There are many reports about the effects of dietary fatty acid composition on volatile flavor compounds of cooked beef, lamb, and pork (Larick et al., 1992; Elmore et al., 1999; Elmore et al., 2000; Lu et al., 2008), however, limited data exists regarding the effect of dietary lipids on volatile flavor compounds of chick meat. It has been shown that the flavor and aroma compounds of chicken meat are due to thermal degradation of lipids, Maillard reaction, and interaction between these two reactions (Brunton et al., 2002). Clostridium butyricum is a butyric acid-producing, sporeforming, gram-positive anaerobe and has functions of improving the composition of gastrointestinal microbiota, enhance humoral immune response and promote digestion (Ito et al., 1997; Song et al., 2006). Our previous studies demonstrated that C. butyricum benefits gut health and immune function of broiler chickens and can increase intramuscular fat content and the contents of eicosapentaenoic acid (EPA) and n-3 PUFA in breast muscle of broilers (Yang et al., 2010; Zhang et al., 2011; Zhao et al., 2013). Therefore, the changed fatty acid composition of chicken meat by C. butyricum may affect the chicken volatile flavor compounds. The purpose of this study was to research the effects of dietary lipids and C. butyricum on fatty acid compositions of breast muscle of broiler and to assess the effect of dietary lipids and C. butyricum on cooked chicken meat flavor by volatile compounds analysis. MATERIALS AND METHODS Birds, livestock management, and diets: A total of 192 one-day-old female broilers were randomly divided into 4 treatment groups consisting of 6 replicates (cages) with 8 chicks per replicate. The temperature of the chicken house *Corresponding author s bingkunzhang@126.com 1 State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Key Laboratory of Feed Safety and Bioavailability, Ministry of Agriculture, Beijing, P.R. China. 2 Beijing University of Agriculture, Beijing, P.R. China.

2 1168 INDIAN JOURNAL OF ANIMAL RESEARCH was maintained at 33 C during the first week, between 28 and 30 C during the subsequent two weeks, and last 3 weeks at 25 C. Twenty-four hour constant light was provided. The four treatments of birds were fed diets containing a) soybean oil without C. butyricum supplementation (SO), b) fish oil without C. butyricum supplementation (FO), c) soybean oil with C. butyricum supplementation (SCB), or d) fish oil with C. butyricum supplementation (FCB). The amount of lipid supplemented to the diet was 40 g/kg for starter and grower diets. The C. butyricum supplemented diets contained CFU/kg of viable organisms. The ingredients and fatty acid compositions of experimental diets are shown in Table1. Experimental procedures were approved and conducted under the guidelines of the China Agricultural University Animal Care and Use Committee. Animal sacrifice and tissue sampling: At 42 day, one chicken was randomly selected from each replicate and sacrificed by exsanguination. The breast muscle was removed and immediately frozen in liquid nitrogen and stored in a freezer at -30 C for future fatty acid analysis with GC and volatile aroma analysis with HPLC-MS. Fatty acid analysis of muscle samples: Breast muscle was freeze-dried to constant weight using Edwards Modulyo freeze drying equipment. All the lipid extractions of samples were transmethylation into fatty acid methyl esters (Sukhija et al., 1988). HP6890 gas chromatograph with flame ionization detector and a DB-23 capillary column was used to separate and authenticate the fatty acid. Carrier gas was helium with about 1.1mL/min flow velocity. The temperature was increased adopting the following procedure: 180 C for ten minutes, and up to 220 C at 4 C per minute, then retained for 15 minutes, finally raised up to 250 C at 3 C per minute. Split ratio was 1:20, added 1 L sample. The injection port s temperature was 250 C. Nonadecane was used as the interior label. The results were represented as milligram quantities of fatty acid in 100g muscle or diet. Volatile flavor compounds analysis: The aroma was determined using the method described by Elmore (2004). The muscle samples volatile compounds were analyzed by GC MS. The breast muscle was cut into rectangular piece weighing about 20g. The meat was put into a 100 ml borosilicate glass reagent bottle with air-tight and PTFElined screw top and then cooked at 130 C for 45 min in autoclave. The volatile compounds were extracted by solid phase micro-extraction (SPME) device and equilibrated at 60 C for 5 minutes after heating in a gas chromatography injector port at 250 C for 30 min. The fibre was exposed to the head space above the sample for 45 min after equilibration. It was then inserted into the SPME device into the injection port of the GC MS system. The gas chromatography mass spectrometry of method adopted was as per Lu (2008). Statistical analysis: All analyses were performed with SPSS Statistics 20 software. The analytic approach was two-way analysis of variance (ANOVA), with lipids and C. butyricum as the fixed factors. Significance was defined at P < RESULTSAND DISCUSSION Fatty acids: Concurring with our previous reports (Zhang et al., 2011), the source of dietary lipid and supplementation of C. butyricum did not affect average daily gain, average daily feed intake and feed conversion ratios of broiler chickens during intervals of days 1 21 or days 1 42 in our present study (Table 2.).The effects of dietary lipids and C. butyricum supplements on the composition of fatty acid are listed in Table 3. While compared with soybean oil, fish oil decreased (P< 0.05) the contents of C18:2n-6, n-6 PUFA, and the ratio of n-6:n-3 fatty acids in breast muscle. However, the contents of C20:5n-3 (P< 0.001), C22:6n-3 (P < 0.05), and n-3 PUFA (P <0.001) were higher (P< 0.05) in the broilers fed the FO diet than the SO diet. This was consistent with our previous report (Yang et al., 2010) that increasing the concentration of n-3pufa in poultry diets by feeding fish oil resulted in an increase in the n-3pufa content of poultry meat. The results were also similar to previous studies, where it was indicated that using oily fish byproducts the content of n-3 fatty acids in poultry meat could be improved (Leskanich and Noble, 1997; Hulan et al., 1988; Yang et al., 2010). Volatile compounds: The flavor compounds of meat include furans, pyrazines, pyrroles, oxazoles, thiophenes,thiazoles and other heterocyclic compounds (Jayasena et al., 2013).The effects of dietary lipids and C. butyricum supplements on the composition of volatile aroma are listed in Table 4. Sixty-six compounds were identified in the headspace extract (concentration 1 ng/100 g meat). These compounds included 14 alkanes, 17aldehydes, 6 alcohols, 9 ketones, 6 furans, 7 nitrogen-containing compounds and 7 sulfur-containing compounds.the type of dietary lipid had a clear effect on octane, hexanal, 2-undecenal, 1- adamantanol, 2-butanone, 2-decanone, 2-Ethylfuran and methoxy phenyl acetone oxime concentrations in cooked bresast muscle. Among them, octane, hexanal, adamantanol, 2-decanone and methoxy phenyl acetone oxime were present in higher levels in soybean oil treatments (P<0.05). Octane, adamantanol and 2-decanone were exclusively present in soybean oil treatments.2-undecenal and 2-butanone were higher in fish oil treatments than soybean oil treatments (P<0.05), and 2- butanone was not found in soybean oil treatments. The addition of C. butyricum significantly increased (P<0.05) the concentrations of O-xylene, dodecane, 2-ethylfuran, trans-2-(2-pentenyl) furan, and 2- methylthiophene. O-xylene, dodecane and e-2-(2-penteny) furan were exclusively detected in C. butyricum treatments. There was a significant interaction effect (P<0.05) on the levels of p-xylene, naphthalene, heptanal, benzaldenhyde,

3 Table 1: Ingredients and composition of dietary treatments. Volume 52 Issue 8 (August 2018) 1169 Item 1 to 21 d 22 to 42 d Soybean oil Fish oil Soybean oil Fish oil Ingredients (g/kg) Corn Soybean meal Soybean oil Fish oil Starch Dicalcium Phosphate Limestone Salt DL- Methionine Lysine-HCl Vitamin and mineral premix a Choline chloride (50%) Ethoxyquinoline (33%) Calculated nutrient (%) ME, kcal/kg CP Lys Met Ca Available P Analyzed fatty acid content (%) C16: C18: C18:1n C18:2n C18:3n C20: C20: C20:5n C22:6n a Mineral and vitamin premix supplied (per kg of final diet): Cu,8 mg (CuSO 4 5H 2 O); Fe, 80 mg (FeSO 4 ); Mn, 100 mg (MnSO 4 H 2 O); Se, 0.15 mg (Na 2 SeO 3 ); I, 0.35 mg (KI); vitamin A, 9, 500 IU (retinylacetate); cholecalciferol, 62.5 g; vitamin K 3, 2.65mg; thiamin, 2mg; riboflavin, 6mg; vitamin B 12, mg; vitamin E, 30 IU ( -tocopherol acetate); biotin, mg; folic acid, 1.25 mg; pantothenic acid 12 mg; niacin, 50 mg. Table 2: The effects of dietary lipids and C. butyricum supplements on growth performance of broiler chickens. Item SO FO SO+CB FO+CB SEM P-Value Lipid CB Lipid CB Days 1 to 21 BWG FI FCR Days 1 to 42 BWG FI FCR SO = dietary soybean oil without C. butyricum supplementation; SO+CB = dietary soybean oil with C. butyricum supplementation ( cfu/kg); FO = dietary fish oil without C. butyricum supplementation; FO+CB = dietary fish oil with C. butyricum supplementation ( cfu/kg); CB = C. butyricum; Lipid CB = interaction between lipids and C. butyricum treatment. NS, not significantly different (P > 0.05); *P <0.05; **P < 0.01; *** P < BWG, body weight gain; FI, feed intake; FCR, feed conversion ratio.

4 1170 INDIAN JOURNAL OF ANIMAL RESEARCH Table 3: The effects of dietary lipids and C. butyricum supplements on the composition of fatty acid. Fatty acid Lipids in breast muscle SEM P-Value (% total fatty acid) SO FO SO+CB FO+CB Lipid CB Lipid CB C14: a 0.85 b 0.53 ab 1.60 c *** ** ** C14: a 0.08 b 0 a 0.10 b *** NS NS C16: NS NS NS C16: a 2.12 b 0.93 a 2.97 c *** NS * C18: a a a b ** NS * C18:1n a b ab ab NS NS * C18:2n a 7.17 b a c *** NS * C18:3n a 0.40 g 1.06 a 0.81 g *** NS * C20: NS NS NS C20: a 0.34 a 0.36 b 0.53 c * ** NS C20: a 0.33 g 1.33 c 0.41 b *** ** NS C20:3n a 0.73 b 1.96 c 0.75 b *** * NS C20:4n a 2.35 b 7.83 a 2.37 b *** NS NS C20:3n a 0.03 ab 0 b 0.03 ab NS * * C20:5n a 3.93 b 0.57 a 3.71 b *** NS NS C22: NS NS NS C22: NS NS NS C22:6n a b 1.63 a b *** NS NS C24: a 3.60 b 1.40 a 3.72 b *** NS NS SFA NS NS NS MUFA NS NS NS PUFA NS NS NS n-6 FA a b a b *** * NS n-3 FA 3.37 a b 2.90 a b *** NS NS n-6:n-3 FA 9.07 a 0.72 b a 0.88 b *** NS NS SO = dietary soybean oil without C. butyricum supplementation; SO+CB = dietary soybean oil with C. butyricum supplementation ( cfu/kg); FO = dietary fish oil without C. butyricum supplementation; FO+CB = dietary fish oil with C. butyricum supplementation ( cfu/kg); CB = C. butyricum; Lipid CB = interaction between lipids and C. butyricum treatment. NS, not significantly different (P > 0.05); *P <0.05; **P < 0.01; *** P < SFA, total saturated fatty acids; MUFA, total monounsaturated fatty acids; PUFA, total polyunsaturated fatty acids. 1-penten-3-ol, 2, 3-pentanedione, 2-methlyfuran, 2- ethylfuran, and 2-methylthiophene in cooked breast muscle. The levels of p-xylene, naphthalene, heptanal, benzaldenhyde, 1-penten-3-ol, 2, 3-pentanedione, 2- methlyfuran, and 2-ethylfuranwere decreased after supplement C. butyricum in fish oil dietary. The levels of benzaldenhyde and 2, 3-pentanedione were increased in cooked breast muscle of broilers fed diets containing soybean oil supplemented with C. butyricum (P<0.05). Aliphatic aldehydes contribute to the fatty flavors of cooked chicken meat, hexanal is the most abundant aldehydes identified in chicken flavor (Jayasena et al., 2013).Hexanal is one of the oxidation products of C18: 2n- 6 (Larick et al., 1992; Elmore et al., 2004). The higher hexanal concentration in cooked chick breast muscle of soybean diet groups is possibly associated with the higher C18: 2n-6 content.2-butanone derived from Maillard reaction and its odour description is chocolate and buttery notes in cooked beef (Machiels et al., 2004). The odour description of 2-undecenal is tallow and sweet and it is one of the the major sources of chicken flavor (Jayasena et al., 2013). Aromatic hydrocarbons are important to the flavor of meat (Min et al., 1979), so the difference in o-xylene may have an effect on meat flavor of C. butyricum treatments. Heptanal, odour description is fruity, it is the product of autoxidation of oleic and linoleic acid (Elmore et al., 1999). Machiels et al. (2004) reported that 2,3-Pentanedione has caramel, buttery and fruity flavor in cooked beef. In this study, only few volatile compounds were affected significantly by the difference between dietary treatments in fatty acid compositions, these indicated that the oxidation degree of lipidis low in chicken muscle. The significance of aroma of the volatile compound not only relies on its concentration but also on its odour threshold, therefore the low odour threshold compounds may still induce different flavor of the cooked meat (Lu et al., 2008). For this reason, analysis of the concentration of aroma compounds and some lower odour threshold Maillard reaction products is meaningful. In comparison with soybean oil treatment, cooked breast muscle from fish oil treatment had lower level of total alkanes, aldehydes, alcohols, nitrogen-containing compounds and sulfur-containing

5 Volume 52 Issue 8 (August 2018) 1171 Table 4: The effects of dietary lipids and C. butyricum supplements on the composition of volatile aroma. Compound Mean concentration in headspace SEM P-Value LRI Confirmation (m/z; relative intensity) (ng/100g meat) method SO FO SO+CB FO+CB Lipid CB Lipid CB Alkanes Benzene NS NS NS 686 ms+lri Methylbenzene NS NS NS 766 ms+lri Octane 6 a 0 b 4 ab 0 b 4 ** NS NS 798 ms+lri P-xylene 1 ab 3 ab 4 a 0 b 3 NS NS * 872 ms+lri Ethylbenzene NS NS NS 864 ms+lri O-xylene NS * NS 869 ms+lri Styrene NS NS NS 892 ms+lri Naphthalene 0 a 8 b 2 a 0 a 5 NS NS ** 1150 ms+lri Undecane NS NS NS 1099 ms+lri Dodecane NS * NS 1199 ms+lri Tetradecane NS NS NS 1400 ms+lri Pentadecane NS NS NS 1499 ms+lri Hexadecane NS NS NS 1614 ms+lri Aldehydes methyl-2-Butenal NS NS NS 807 ms+lri Hexanal 496 a 93 b 188 ab 67 b 333 * NS NS 836 ms+lri Heptanal 34 ab 50 a 43 a 20 b 19 NS NS ** 909 ms+lri E-2-Heptenal NS NS NS 962 ms+lri Benzaldehyde NS NS * 965 ms+lri N-octylaldehyde NS NS NS 1003 ms+lri Phenylacetaldehyde NS NS NS 1065 ms+lri (E)-2-Octenal NS NS NS 1060 ms+lri Nonanal NS NS NS 1103 ms+lri (E)-2-nonanal NS NS NS 1136 ms+lri Decanal NS NS NS 1204 ms+lri (E)-2-Decenal NS NS NS 1248 ms+lri 2-Undecenal 7 a 23 a 0 a 106 b 73 * NS NS 1353 ms+lri Dodecanal NS NS NS 1395 ms+lri Myristic aldehyde NS NS NS 1553 ms+lri Palmitaldehyde NS NS NS 1748 ms+lri Stearaldehyde NS NS NS 2036 ms+lri Alcohols Penten-3-ol 0 a 5 b 2 ab 0 a 9 NS NS * 986 ms+lri 1- hexanol NS NS NS 870 ms+lri 1-octene-3-alcohol NS NS NS 953 ms+lri Octanol NS NS NS 1049 ms+lri (E)-Oct-2-en-1-ol NS NS NS 1068 ms+lri Continue Table 4

6 1172 INDIAN JOURNAL OF ANIMAL RESEARCH Continue Table 4 1-Adamantanol 7 a 0 b 4 a 0 b 5 ** NS NS 1082 ms+lri Ketones Butanone 0 a 27 ab 0 a 101 b 72 * NS NS 668 ms+lri 2,3-Pentanedione 0 a 8 ab 19 b 1 ab 15 NS NS * 693 ms+lri 2-Pentanone NS NS NS 639 ms+lri 1-hydroxy-2-Propanone NS NS NS 694 ms+lri 3-hydroxy-2-Butanone NS NS NS 708 ms+lri 2-Heptanone NS NS NS 843 ms+lri 2-Nonanone NS NS NS 1092 ms+lri 2-Decanone 10 ab 0 a 15 b 0 a 10 ** NS NS 1192 ms+lri 2-Pentadecanone NS NS NS 1571 ms+lri Furans Methylfuran 0 a 36 b 18 ab 0 a 26 NS NS * 668 ms+lri 2-Ethylfuran 25 a 204 b 43 a 0 a 99 * ** ** 700 ms+lri Furfural NS NS NS 833 ms+lri Furfuralcohol NS NS NS 896 ms+lri 2-Pentylfuran NS NS NS 981 ms+lri Trans-2-(2-Pentenyl)furan 36 a 191 b 20 a 0 a 134 NS * NS 998 ms+lri Nitrogen-containing Pyrrole NS NS NS 751 ms+lri Pyrazine NS NS NS 744 ms+lri 2-methylpyrazine NS NS NS 803 ms+lri Oxime-, methoxy-phenyl- 8 ab 5 ab 10 a 0 b 8 * NS NS 896 ms+lri 2,5 and 2,6-Dimethylpyrazine NS NS NS 907 ms+lri Ethyl-pyrazine NS NS NS 916 ms+lri Sulfur-containing Thiophene NS NS NS 690 ms+lri Dimethyl trisulfide NS NS NS 915 ms+lri 2-Methylthiophene 39 a 0 a 34 a 80 b 41 NS * * 821 ms+lri 3-Thiophenecarboxaldehyde NS NS NS 999 ms+lri 2-Thiophenecarboxaldehyde NS NS NS 998 ms+lri 2-Acetylthiazole NS NS NS 1014 ms+lri 5-Methyl-2-thiophenecarboxaldehyde NS NS NS 1063 ms+lri SO = dietary soybean oil without C. butyricum supplementation; SO+CB = dietary soybean oil with C. butyricum supplementation ( cfu/kg); FO = dietary fish oil without C. butyricum supplementation; FO+CB = dietary fish oil with C. butyricum supplementation ( cfu/kg); CB = C. butyricum; Lipid CB = interaction between lipids and C. butyricum treatment. *P <0.05; **P < 0.01; NS = not significant (P>0.05).

7 compounds. It indicated that fish oil has a negative effect on flavor of chicken meat. It is similar to the result of Poste s reporter, which indicated that fish meal influenced the chicken meat s flavor negatively (Poste, 1990). Cooked breast muscle of chicken fed fish oil dietary supplement with C. butyricum had higher levels of total aldehydes, alcohols, ketones, furans, and sulfur-containing compounds than those fed fish oil dietary without C. butyricum supplement. Sulfurcontaining heterocyclic compounds have low odour thresholds with meaty aromas (Jayasena et al., 2013). This may indicate that the flavor of cooked chicken breast meat can be improved by supplementation of C. butyricum in fish oil dietary. Volume 52 Issue 8 (August 2018) 1173 CONCLUSION Fish oil diets can increase the n-3pufa content of poultry meat, but lower flavor of cooked chicken. The lower flavor can be improved by supplementing with C. butyricumin dietary. The mechanism of dietary effect on the flavor of cooked muscle needs more research, in order to produce products with high level of nutrition and good sense of flavor. ACKNOWLEDGEMENT The authors thank Dr. Jianmin Yuan and Yuxin Shao for their help with the experiments. This work was supported by the National Key Technology R&D Program of China during the 12th five-year plan (2011BAD26B04) and the Chinese Universities Scientific Fund (No. 2015DK005). REFERENCES Brunton, N.P., Cronin, D.A., and Monahan, F.J. (2002). Volatile components associated with freshly cooked and oxidized off flavours in turkey breast meat. Flavour Frag. J.17: Elmore, J.S., Mottram, D.S., Enser, M., and Wood, J.D. (1999). Effect of the polyunsaturated fatty acid composition of beef muscle on the profile of aroma volatiles. J. Agr. Food Chem.47: Elmore, J.S., Mottram, D.S., Enser, M., and Wood, J.D. (2000). The effects of diet and breed on the volatile compounds of cooked lamb. 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