- Email: [email protected]
Effect of replacement of a conventional diet by granulated barley during finishing period on growth performance and carcass and meat characteristics in 130-kg gilts
Livestock Science 148 (2012) 196–200
Contents lists available at SciVerse ScienceDirect
Livestock Science journal homepage: www.elsevier.com/locate/livsci
Short communication
Effect of replacement of a conventional diet by granulated barley during finishing period on growth performance and carcass and meat characteristics in 130-kg gilts A. Daza a, M.A. Latorre b,n, A. Olivares c, D. Amaza´n c, C.J. Lo´pez Bote c a b c
´n Animal, Escuela Te´cnica Superior de Ingenieros Agro ´nomos, Universidad Polite´cnica, Ciudad Universitaria, 28040 Madrid, Spain Departamento de Produccio ´n Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain Departamento de Produccio ´n Animal, Facultad de Veterinaria, Universidad Complutense, Ciudad Universitaria, 28040 Madrid, Spain Departamento de Produccio
a r t i c l e in f o
abstract
Article history: Received 14 December 2011 Received in revised form 14 May 2012 Accepted 24 May 2012
A total of 48 Duroc (Landrace Large White) gilts of 40.5 70.69 kg of initial body weight (BW) were used. During the growing period (40–100 kg BW), all pigs ate a conventional feed and during the finishing period (100–130 kg BW) animals received the experimental dietary treatments; a conventional feed based on barley, wheat and vegetable meals (control diet; 9.06 MJ of net energy/kg and 10.78% of crude protein) or a feed with 98.5% of granulated barley (barley diet; 9.63 MJ of net energy/kg and 8.96% of crude protein). There were twelve replicates of two pigs per treatment. Pigs were slaughtered at 130 7 1.66 kg BW because they were intended for dry-cured ham production. For the overall period, no differences were observed for average daily gain and feed conversion ratio, although the average daily feed intake was lower (P o 0.05) and also the feeding costs (P o 0.01) in pigs fed granulated barley than in pigs fed control diet. The treatment had no significant effect on carcass characteristics except for sirloin weight and yield which were lower (P o 0.01) in gilts fed barley diet than in those fed control diet. No differences between treatments were detected in meat characteristics or fatty acid profile of subcutaneous and intramuscular fat of the longissimus thoracis muscle (P 40.05). It is concluded that the replacement of a conventional feed by a diet based on barley from 100 and 130 kg BW had scarce effect on carcass and meat traits, without any penalisation of productive performance and with reduced feeding costs. Therefore, the use of granulated barley provided during finishing period might be interesting for heavy pigs. & 2012 Elsevier B.V. All rights reserved.
Keywords: Barley Growth performance Carcass Meat Fat Heavy gilts
1. Introduction Spain is the world leader in the elaboration of drycured ham with a total production of 245,000 t in 2010. Currently, minimum levels of carcass weight and fat depth at gluteus medius muscle (m. GM) are required to improve uniformity and quality of the end product. In
n Corresponding author. Tel.: þ 34 876554168; fax: þ34 976761612. E-mail address: [email protected] (M.A. Latorre).
1871-1413/$ - see front matter & 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.livsci.2012.05.021
addition, it is widely accepted that intramuscular fat (IMF) and fatty acid (FA) profile are very important meat quality characteristics (Fernandez et al., 1999). Some nutritional and management strategies have been carried out in pigs intended to dry-cured products to increase carcass fat thickness and IMF content in pork, especially in gilts due to lower fat deposition than in barrows (Latorre et al., 2009). Thus, for example, it has been reported that reductions of protein/digestible energy ratio lead to a higher backfat depth and IMF percentage (D’Souza et al., 2003). Moreover, a negative association between dietary vitamin A
A. Daza et al. / Livestock Science 148 (2012) 196–200
and IMF proportion has been observed in pigs (Olivares et al., 2009a). In a recent study, Daza et al. (2010, in press) found that the use of barley as single ingredient from 80 to 90 kg of body weight (BW) to the slaughter led to enhanced IMF content, its proportion in C18:1n-9 and some variables related to meat colour in heavy barrows, but impaired feed efficiency. The acceptable price and nutritional composition (FEDNA, 2010) of this cereal make it interesting to study as the very main ingredient in diets for pigs during growing. In this context, our hypothesis is that the use of granulated barley from 100 to 130 kg BW might carry out desirable effects on carcass and meat quality of heavy pigs and/or no impairment of feed conversion ratio and lower feeding costs. Therefore, the aim of the current experiment was to study the influence of the substitution of a conventional feed by barley during finishing period on growth performance and carcass and meat quality of gilts intended for dry-cured ham production. 2. Material and methods 2.1. Experimental design and growth performance All the experimental procedures used in the trial were in compliance with the Spanish guidelines for the care and use of animals in research (Boletin Oficial Estado, 2007). A total of 48 Duroc (Landrace Large White) gilts of 40.570.69 kg of initial BW were used. At the arrival to the experimental farm, animals were housed in a controlled environment barn and were randomly allotted to 24 pens. From the beginning of the trial to 10070.85 kg BW, all pigs ate a conventional feed for growing. Thereafter until slaughter (130 71.66 kg BW), animals received the experimental dietary treatments; a conventional feed (control diet) or a feed based mainly on granulated barley (barley diet). Each treatment was replicated 12 times being the pen with 2 pigs considered as the replicate. The composition and the estimated (FEDNA, 2010) and analysed nutrient value (AOAC, 2000) of feeds are shown in Table 1. Pigs had free access to pelleted feed and water through the trial. Individual BW and feed consumption per pen were recorded at the beginning, 53 days later and at the end of trial and were used to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) for each replicate. Additionally, the costs of feeding per kg of BW were calculated considering the prices of commercial feedstuff and barley as 0.27 and 0.23 h/kg, respectively. 2.2. Slaughtering, sampling and carcass measurements On the day before slaughter, pigs were individually weighed and backfat depth was measured by a real-time ultrasound apparatus RTU (Kretz Technick Inc., 600 V-32, Sonovet, Austria) as described by Daza et al. (in press). Thereafter, pigs were transported to a commercial abattoir where they were electrically stunned, slaughtered and eviscerated according to standard commercial
197
Table 1 Composition and nutrient content of the experimental diets (g kg 1, asfed basis unless otherwise indicated). Growing diet
Ingredients Barley Wheat Rapeseed meal 330 g kg 1 CP Sunflower meal 280 g kg 1 CP Sugarcane molasses Soybean meal 440 g kg 1 CP Fat Calcium carbonate Dicalcium phosphate Salt Lysine 50% Methionine Threonine Premix vitamin–mineral a Estimated nutrient contentb Net energy (MJ/kg) Dry matter Crude protein (CP) Crude fibre Ether extract Fatty acids C14:0 C16:0 C18:0 C18:1n-9 C18:2n-6 C18:3n-3 Determined nutrient contentc Dry matter Crude protein Crude fibre Ether extract Fatty acids C14:0 C16:0 C18:0 C18:1n-9 C18:2n-6 C18:3n-3
Finishing diets Control
Barley
630.3 120.4 – – – 200.4 11.1 15.0 5.50 5.00 9.00 0.70 0.60 2.00
643.7 100.0 147.1 50.0 20.0 – 10.0 12.2 2.60 5.00 6.50 0.50 0.40 2.00
985.0 – – – – – – 10.0 2.50 2.50 – – – –
9.52 890.2 177.7 43.6 29.7
9.06 885.7 141.8 62.7 27.2
9.63 894.7 94.6 46.3 17.7
0.22 5.17 0.78 6.50 7.96 0.88
0.20 4.72 1.58 6.80 6.88 0.84
– 3.15 – 1.77 7.68 0.78
884.8 165.5 44.6 28.2
887.8 107.8 66.5 28.3
893.9 89.6 49.5 17.5
0.18 2.38 0.16 6.51 7.89 0.81
0.49 2.19 0.72 5.48 10.23 0.64
0.20 3.19 0.29 1.52 8.14 0.09
a Supplied per kg diet: vitamin A (trans-retinyl acetate) 8500 IU; vitamin D3 (cholecalciferol) 1500 IU; vitamin E (a-tocopherol acetate) 15 IU; Cu (as copper sulphate) 10 mg. b According to FEDNA (2010). c According to AOAC (2000).
procedures. Hot carcass weight was individually recorded and used to calculated carcass yield. At 45 min postmortem, carcass length, ham length, ham perimeter and fat depth over at m. GM were measured on the left side of each carcass as described by Latorre et al. (2009). After 6 h of refrigeration, carcasses were processed and hams, forelegs, loins and sirloins were weighed to calculate their yield in carcass. After collection of carcass data, a total of 32 carcasses equally distributed among treatments were randomly selected for the meat and fat evaluation. From each left side of them, a section of 400 725 g of longissimus thoracis muscle (m. LT) was excised at the last rib and a subcutaneous fat sample including fat layers, skin
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A. Daza et al. / Livestock Science 148 (2012) 196–200
and lean was taken at the tail insertion in the coxal region and moved to the laboratory.
Table 2 Effect of dietary treatment on growth performance of heavy gilts. Item
a
Control
2.3. Laboratorial determinations for meat and fat samples At 8 h postmortem, colour was evaluated on subcutaneous fat and m. LT samples with a chromameter (CM 2002, Minolta Camera, Osaka, Japan), using objective measurements, as described by Latorre et al. (2009). The chromameter also provided the content in oxymyoglobin and metmyoglobin in the muscle. After measuring the colour variables, all samples were placed in individual plastic bags and vacuum-packaged at 20 1C until subsequent analyses. After 3 weeks, the samples were thawed for 24 h at 4 1C, removed from packages and blotted dry for 20 min. In the m. LT samples, moisture was determined by oven drying method (at 103 1C during 48 h) and lipids following the method proposed by Folch et al. (1957). Lipids from subcutaneous fat were extracted by the procedure developed by Bligh and Dyer (1959) and lipids of diets were extracted and quantified by Sukhija and Palmquist (1988). The FA methyl esters were analysed as described by Daza et al. (in press) using a gas chromatograph (Model HP6890, Hewlett Packard Co., Avondale, PA, USA). 2.4. Statistical analyses Data were analysed using the statistical package SAS (1999). The model included the dietary treatment as fixed effect and a covariate when was significant (the initial BW for growth performance traits and the carcass weight for carcass characteristics). Each treatment was replicated 12 times for productive performance and carcass variables (experimental unit¼the pen with 2 pigs) and 16 times for the meat and fat traits (the experimental unit¼the animal). 3. Results and discussion 3.1. Growth performance Gilts fed control diet from 100 to 130 kg BW ate 2.4% more feed (P o0.001) and tended to grow 11% faster (P¼0.08) than gilts fed barley diet (Table 2). Feeding costs were 0.03 h/kg BW more expensive (Po0.01) in pigs fed control diet than in pigs fed barley diet. The feeding costs in heavy pigs are especially important during the finishing period, and a diet based on barley would provide a cheaper feedstuff, taking into account that a possible supplementation of vitamins and minerals could be required. Recently, Daza et al. (in press) observed in gilts of BW ranging from 45 to 92 kg that the substitution of a conventional feed by a diet with barley as the only major ingredient (974.7 g kg 1) led to a reduction of ADG and an increase of ADFI and FCR. Previously, Daza et al. (2010) did not find differences for ADG and ADFI between gilts fed only granulated barley and those fed a control diet from 86 to 130 kg BW. However, FCR was worse by 13% and production costs were lower by 0.09 h/kg BW in those fed barley. These results may be due to the lack of salt, calcium and phosphate sources in the diet.
Evolution of pig BW (kg) Initial 40.0 53 days laterc 99.0 At slaughter 130.7 From 40 to 100 kg BW ADG (kg) ADFI (kg) FCR
Barley diet
SEM (n¼ 12)
Significance
41.0 100.8 129.1
0.69 0.85 1.66
NS NS NS
b
0.914 2.68 2.94
0.942 2.66 2.85
0.013 0.014 0.045
NS NS NS
From 100 to 130 kg BW ADG (kg) 0.928 ADFI (kg) 2.96 FCR 3.19
0.836 2.89 3.46
0.036 0.010 0.187
0.08
0.904 2.75 3.07 0.47
0.017 0.012 0.063 0.007
NS
From 40 to 130 kg BW ADG (kg) ADFI (kg) FCR Feeding costs (h/kg BW)
0.920 2.79 3.03 0.50
nnn
NS
n
NS nn
*P o0.05; **Po 0.01; ***Po 0.001. a BW: body weight; ADG: average daily gain; ADFI: average daily feed intake; FCR: feed conversion ratio. b Twelve pens of two pigs each per treatment. c The beginning of the experimental diets.
3.2. Carcass quality The treatments had no effect on carcass traits except for some primal cuts (Table 3); pigs fed control diet had heavier sirloin by 0.05 kg (Po0.01) and higher yield of this piece in the carcass (Po0.01) than pigs fed barley diet. Moreover, pigs fed control diet tended to have heavier loin by 0.1 kg (P¼0.07) and higher loin yield in carcass (P¼0.06) than those fed control diet. In this line, Daza et al. (in press) observed a lower loin weight in pigs fed barley from 92 to 130 kg BW than in pigs fed conventional feed, but no differences were found for ham and foreleg weights or percentage in carcass. In the current trial, the lower protein level provided by barley diet did not affect significantly the backfat depth at the level of m. GM, although it was numerically lower by 8.4% in pigs fed control diet (P¼0.14). Daza et al. (2010, in press) found similar results in heavy pigs fed mainly barley during growing–finishing periods. However, Rodriguez-Sanchez et al. (2011) observed that a reduction of dietary lysine content from 0.70 to 0.60% (from 14.5 to 14.0% of crude protein) in pigs from 100 to 130 kg BW tended to increase fat depth at m. GM by 2.4 mm. Probably, in the present work, the protein content provided in barley diet was not low enough to significantly enhance the backfat level of this muscle in this kind of pigs. When diets were formulated, a higher reduction of protein:energy ratio was planned (around 32%) in the barley diet in comparison to control diet but in the laboratorial analysis of the feeds only a 13.5% was obtained. For dry-cured ham production in Spain, the backfat depth at m. GM is one of the main requirements to select suitable carcasses at the slaughterhouse.
A. Daza et al. / Livestock Science 148 (2012) 196–200
Table 3 Effect of dietary treatment on carcass characteristics of heavy gilts. Control Barley
SEM (n¼ 12)
Significance
103.1 79.4
103.7 79.7
1.84 0.32
NS NS
85.7 38.5 77.9
85.6 38.4 77.4
0.47 0.21 0.34
NS NS NS
26.6 20.9
25.2 22.8
0.80 0.88
NS NS
Main cut weight (kg) Ham Foreleg Loin Sirloin Total a
3.5 8.3 3.2 0.44 25.4
13.4 8.4 3.1 0.39 25.3
0.08 0.07 0.05 0.01 0.38
NS NS 0.07
Main cut yield (% carcass) Ham Foreleg Loin Sirloin Total a
13.1 8.1 3.1 0.42 24.6
13.0 8.0 2.9 0.37 24.5
0.08 0.07 0.05 0.01 0.14
Carcass Weight (kg) Yield (%) Size measurements (cm) Carcass length Ham length Ham perimeter Fat depth (mm) By ultrasounds in vivo At Gluteus medius muscle postmortem
nn
NS NS NS 0.06 nn
NS
**P o 0.01. a Total ¼ hamþforeleg þ loinþ sirloin.
3.3. Meat and fat quality No effect of dietary treatment was observed on meat characteristics (data not shown). In accordance with the results of the current trial, Daza et al. (in press) reported that the replacement of conventional feed by a diet based on barley after 92 kg BW did not affect the muscle colour variables. Also, Rodriguez-Sanchez et al. (2011) observed no effect of the reduction of protein or lysine/energy ratio on colour traits. The moisture and IMF percentages obtained were 76.5 and 77.3% (P¼0.36) and 5.87 and 4.82% (P¼0.14) in control and barley pig meats, respectively. These results are in discordance with data found in other experiments which have shown an increase in IMF content of pork with a reduction of protein/energy ratio by 21% (Daza et al., in press) or 32% (Daza et al., 2010). In the current experiment, and as also noted in an explanation about backfat depth, the low reduction of protein/ energy ratio (13.5%) in the barley diet in comparison with control diet might not have been enough to increase IMF content in pigs fed barley. The lower numerical value of IMF percentage observed in meat from gilts fed barley in the present work (4.82 vs. 5.87%) could be due, at least in part, to the lack of vitamin and mineral premix in that diet, especially vitamin A. The effect of dietary vitamin A on IMF content is controversial and there is limited information on this topic in swine. D’Souza et al. (2003) found a higher IMF content in loin from lean pigs when vitamin A was completely removed from the vitamin– mineral complex, whereas Olivares et al. (2009a) observed no effect of vitamin A in a similar situation.
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Based on the inhibitory effect of retinoids in cultured preadipocyte differentiation (Brandebourg and Hu, 2005), it has been proposed that the effect of vitamin A level on IMF is mediated by adipocyte differentiation (Dimaculangan et al., 1994). In the current experiment, that cell differentiation had to be occurred before the replacement of finishing conventional diet by granulated barley when no vitamin A was provided. No differences were detected between treatments in the major FA proportions of the subcutaneous fat (data not shown) suggesting that the lower crude protein content and the lack of vitamin–mineral complex in the barley diet in comparison to the control had scarce effect on FA composition of pigs. These results agree with data from Daza et al. (in press). Also, Olivares et al. (2009b) did not detect any influence of dietary vitamin A level in finishing diet on FA pattern of subcutaneous backfat outer and inner layers. It is important to note that C18:2 content in subcutaneous fat was around 10% in pigs fed both diets which is positive because a higher value than 12% is not recommended for transformation and conservation processes of meat (Wood et al., 2008). The diet only had a clear effect on C17:0 of IMF from m. LT which was higher in control than in barley gilts (Po0.05) which agrees with data from Daza et al. (2010). In the current study, the control diet, that included higher vitamin A level, showed a tendency to increase total saturated FA (P¼0.16) and decreased total monounsaturated FA (P¼0.15) proportions, but no influence on total polyunsaturated FA proportion was observed. The desaturation indexes C16:1n-7/C16:0, C18:1n-9/C18:0 and monounsaturated FA/saturated FA were lower in control than in barley gilts. Olivares et al. (2009b) reported that the dietary vitamin A increased significantly saturated FA and decreased monounsaturated FA in IMF from fatty pigs and, as in our experiment, no significant effect on polyunsaturated FA was found. 4. Conclusion It is concluded that in finishing production of gilts intended for dry-cured products, replacement of a conventional feed with granulated barley could reduce feed intake and feed costs, without causing effect on carcass, meat and fat traits of pigs, except a reduced weight of the sirloin. Conflict of interest statement No conflict of interest has influenced the development of the work titled: ‘‘Effect of replacement of a conventional diet by granulated barley during finishing period on growth performance and carcass and meat characteristics in 130kg gilts’’.
Acknowledgements This research was supported by Project PET-200708C11-05 (INIA).
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References AOAC, 2000. Official Methods of Analysis. AOAC, Arlington, VA. Bligh, E.G., Dyer, W.J., 1959. A rapid method of total lipid extraction and purification. Can. J. Biochem. Phys. 37, 911–917. Boletin Oficial Estado, 2007. Ley 32/2007 de 7 de Noviembre para el cuidado de los animales, en su explotacio´n, transporte, experimentacio´n y sacrificio. BOE, vol. 268, pp. 45914–45920. Brandebourg, T.D., Hu, C.Y., 2005. Regulation of differentiating pig preadipocytes by retinoic acid. J. Anim. Sci. 83, 98–107. Daza, A., Latorre, M.A., Lo´pez Bote, C.J., 2010. The use of barley as single ingredient in the diet provided during the finishing period may improve the meat quality of heavy pigs from PO Teruel ham (Spain). Span. J. Agric. Res. 8, 607–616. Daza, A., Latorre, M.A., Lo´pez-Bote, C.J. The effect of granulated barley as only ingredient in the growing or finishing diet on productive performance, carcass, meat and fat quality of heavy pigs. Animal (ANIMAL11-60669), http://dx.doi.org/10.1017/S1751731112000110, in press. Dimaculangan, D.D., Chawla, A., Boak, A., Kagan, H.M., Lazar, M.A., 1994. Retinoic acid prevents downregulation of RAS recision genelysyl oxidase early in adipocyte differentiation. Differentiation 58, 47–52. D’Souza, D.N., Pethick, D.W., Dunshea, F.R., Pluske, J.R., Mullan, B.P., 2003. Nutritional manipulation increases intramuscular fat levels in the Longissimus dorsi of female finisher pigs. Aust. J. Agric. Res. 54, 745–749. FEDNA, 2010. Normas FEDNA de composicio´n y valor nutritivo de alimentos para la fabricacio´n de piensos compuestos. In: De Blas, ˜ ola C., Mateos, G.G., Garcı´a-Rebollar, P.G. (Eds.), Fundacio´n Espan Desarrollo Nutricio´n Animal3rd ed. .
Fernandez, X., Moning, G., Talmant, A., Mourot, J., Lebret, B., 1999. Influence of intramuscular fat content on the quality of pigs meat. 1. Composition of the lipid fraction and sensory characteristics of m longissimus lumborum. Meat Sci. 53, 59–65. Folch, J., Lees, M., Stanly, G.H., 1957. A simple method for the isolation and purification of total lipids from animal tissues. J. Biol. Chem. 266, 497–509. ˜ o, L., 2009. The increase Latorre, M.A., Ripoll, G., Garcı´a-Belenguer, E., Arin of slaughter weight of gilts as strategy to optimize de production of Spanish high quality dry-cured hams. J. Anim. Sci. 87, 1464–1471. Olivares, A., Daza, A., Rey, A.I., Lo´pez Bote, C.J., 2009a. Dietary vitamin A concentration alters fatty acid composition in pigs. Meat Sci. 81, 295–299. Olivares, A., Daza, A., Rey, A.I., Lo´pez Bote, C.J., 2009b. Interactions between genotype, dietary fat saturation and vitamin A concentration on intramuscular fat content and fatty acid composition in pigs. Meat Sci. 82, 6–12. Rodriguez-Sanchez, J.A., Sanz, M.A., Blanco, M., Serrano, M.P., Joy, M., Latorre, M.A., 2011. The influence of dietary lysine restriction during the finishing period on growth performance and carcass, meat, and fat characteristics of barrows and gilts intended for dry-cured ham production. J. Anim. Sci. 89, 3651–3662. SAS, 1999. SAS institute user’s guide: statistics, Statistical Analysis Systems. Version 64th ed.. Sukhija, P.S., Palmquist, D.L., 1988. Rapid method for determination of total fatty acid content and composition of feedstuffs and feces. J. Agric. Food Chem. 36, 1202–1206. Wood, J.D., Enser, M., Fisher, A.V., Nute, G.R., Sherad, P.R., Richardson, R.I., Hughes, S.I., Whittington, F.M., 2008. Fat deposition, fatty acid composition and meat quality: a review. Meat Sci. 78, 343–358.
Contents lists available at SciVerse ScienceDirect
Livestock Science journal homepage: www.elsevier.com/locate/livsci
Short communication
Effect of replacement of a conventional diet by granulated barley during finishing period on growth performance and carcass and meat characteristics in 130-kg gilts A. Daza a, M.A. Latorre b,n, A. Olivares c, D. Amaza´n c, C.J. Lo´pez Bote c a b c
´n Animal, Escuela Te´cnica Superior de Ingenieros Agro ´nomos, Universidad Polite´cnica, Ciudad Universitaria, 28040 Madrid, Spain Departamento de Produccio ´n Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain Departamento de Produccio ´n Animal, Facultad de Veterinaria, Universidad Complutense, Ciudad Universitaria, 28040 Madrid, Spain Departamento de Produccio
a r t i c l e in f o
abstract
Article history: Received 14 December 2011 Received in revised form 14 May 2012 Accepted 24 May 2012
A total of 48 Duroc (Landrace Large White) gilts of 40.5 70.69 kg of initial body weight (BW) were used. During the growing period (40–100 kg BW), all pigs ate a conventional feed and during the finishing period (100–130 kg BW) animals received the experimental dietary treatments; a conventional feed based on barley, wheat and vegetable meals (control diet; 9.06 MJ of net energy/kg and 10.78% of crude protein) or a feed with 98.5% of granulated barley (barley diet; 9.63 MJ of net energy/kg and 8.96% of crude protein). There were twelve replicates of two pigs per treatment. Pigs were slaughtered at 130 7 1.66 kg BW because they were intended for dry-cured ham production. For the overall period, no differences were observed for average daily gain and feed conversion ratio, although the average daily feed intake was lower (P o 0.05) and also the feeding costs (P o 0.01) in pigs fed granulated barley than in pigs fed control diet. The treatment had no significant effect on carcass characteristics except for sirloin weight and yield which were lower (P o 0.01) in gilts fed barley diet than in those fed control diet. No differences between treatments were detected in meat characteristics or fatty acid profile of subcutaneous and intramuscular fat of the longissimus thoracis muscle (P 40.05). It is concluded that the replacement of a conventional feed by a diet based on barley from 100 and 130 kg BW had scarce effect on carcass and meat traits, without any penalisation of productive performance and with reduced feeding costs. Therefore, the use of granulated barley provided during finishing period might be interesting for heavy pigs. & 2012 Elsevier B.V. All rights reserved.
Keywords: Barley Growth performance Carcass Meat Fat Heavy gilts
1. Introduction Spain is the world leader in the elaboration of drycured ham with a total production of 245,000 t in 2010. Currently, minimum levels of carcass weight and fat depth at gluteus medius muscle (m. GM) are required to improve uniformity and quality of the end product. In
n Corresponding author. Tel.: þ 34 876554168; fax: þ34 976761612. E-mail address: [email protected] (M.A. Latorre).
1871-1413/$ - see front matter & 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.livsci.2012.05.021
addition, it is widely accepted that intramuscular fat (IMF) and fatty acid (FA) profile are very important meat quality characteristics (Fernandez et al., 1999). Some nutritional and management strategies have been carried out in pigs intended to dry-cured products to increase carcass fat thickness and IMF content in pork, especially in gilts due to lower fat deposition than in barrows (Latorre et al., 2009). Thus, for example, it has been reported that reductions of protein/digestible energy ratio lead to a higher backfat depth and IMF percentage (D’Souza et al., 2003). Moreover, a negative association between dietary vitamin A
A. Daza et al. / Livestock Science 148 (2012) 196–200
and IMF proportion has been observed in pigs (Olivares et al., 2009a). In a recent study, Daza et al. (2010, in press) found that the use of barley as single ingredient from 80 to 90 kg of body weight (BW) to the slaughter led to enhanced IMF content, its proportion in C18:1n-9 and some variables related to meat colour in heavy barrows, but impaired feed efficiency. The acceptable price and nutritional composition (FEDNA, 2010) of this cereal make it interesting to study as the very main ingredient in diets for pigs during growing. In this context, our hypothesis is that the use of granulated barley from 100 to 130 kg BW might carry out desirable effects on carcass and meat quality of heavy pigs and/or no impairment of feed conversion ratio and lower feeding costs. Therefore, the aim of the current experiment was to study the influence of the substitution of a conventional feed by barley during finishing period on growth performance and carcass and meat quality of gilts intended for dry-cured ham production. 2. Material and methods 2.1. Experimental design and growth performance All the experimental procedures used in the trial were in compliance with the Spanish guidelines for the care and use of animals in research (Boletin Oficial Estado, 2007). A total of 48 Duroc (Landrace Large White) gilts of 40.570.69 kg of initial BW were used. At the arrival to the experimental farm, animals were housed in a controlled environment barn and were randomly allotted to 24 pens. From the beginning of the trial to 10070.85 kg BW, all pigs ate a conventional feed for growing. Thereafter until slaughter (130 71.66 kg BW), animals received the experimental dietary treatments; a conventional feed (control diet) or a feed based mainly on granulated barley (barley diet). Each treatment was replicated 12 times being the pen with 2 pigs considered as the replicate. The composition and the estimated (FEDNA, 2010) and analysed nutrient value (AOAC, 2000) of feeds are shown in Table 1. Pigs had free access to pelleted feed and water through the trial. Individual BW and feed consumption per pen were recorded at the beginning, 53 days later and at the end of trial and were used to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) for each replicate. Additionally, the costs of feeding per kg of BW were calculated considering the prices of commercial feedstuff and barley as 0.27 and 0.23 h/kg, respectively. 2.2. Slaughtering, sampling and carcass measurements On the day before slaughter, pigs were individually weighed and backfat depth was measured by a real-time ultrasound apparatus RTU (Kretz Technick Inc., 600 V-32, Sonovet, Austria) as described by Daza et al. (in press). Thereafter, pigs were transported to a commercial abattoir where they were electrically stunned, slaughtered and eviscerated according to standard commercial
197
Table 1 Composition and nutrient content of the experimental diets (g kg 1, asfed basis unless otherwise indicated). Growing diet
Ingredients Barley Wheat Rapeseed meal 330 g kg 1 CP Sunflower meal 280 g kg 1 CP Sugarcane molasses Soybean meal 440 g kg 1 CP Fat Calcium carbonate Dicalcium phosphate Salt Lysine 50% Methionine Threonine Premix vitamin–mineral a Estimated nutrient contentb Net energy (MJ/kg) Dry matter Crude protein (CP) Crude fibre Ether extract Fatty acids C14:0 C16:0 C18:0 C18:1n-9 C18:2n-6 C18:3n-3 Determined nutrient contentc Dry matter Crude protein Crude fibre Ether extract Fatty acids C14:0 C16:0 C18:0 C18:1n-9 C18:2n-6 C18:3n-3
Finishing diets Control
Barley
630.3 120.4 – – – 200.4 11.1 15.0 5.50 5.00 9.00 0.70 0.60 2.00
643.7 100.0 147.1 50.0 20.0 – 10.0 12.2 2.60 5.00 6.50 0.50 0.40 2.00
985.0 – – – – – – 10.0 2.50 2.50 – – – –
9.52 890.2 177.7 43.6 29.7
9.06 885.7 141.8 62.7 27.2
9.63 894.7 94.6 46.3 17.7
0.22 5.17 0.78 6.50 7.96 0.88
0.20 4.72 1.58 6.80 6.88 0.84
– 3.15 – 1.77 7.68 0.78
884.8 165.5 44.6 28.2
887.8 107.8 66.5 28.3
893.9 89.6 49.5 17.5
0.18 2.38 0.16 6.51 7.89 0.81
0.49 2.19 0.72 5.48 10.23 0.64
0.20 3.19 0.29 1.52 8.14 0.09
a Supplied per kg diet: vitamin A (trans-retinyl acetate) 8500 IU; vitamin D3 (cholecalciferol) 1500 IU; vitamin E (a-tocopherol acetate) 15 IU; Cu (as copper sulphate) 10 mg. b According to FEDNA (2010). c According to AOAC (2000).
procedures. Hot carcass weight was individually recorded and used to calculated carcass yield. At 45 min postmortem, carcass length, ham length, ham perimeter and fat depth over at m. GM were measured on the left side of each carcass as described by Latorre et al. (2009). After 6 h of refrigeration, carcasses were processed and hams, forelegs, loins and sirloins were weighed to calculate their yield in carcass. After collection of carcass data, a total of 32 carcasses equally distributed among treatments were randomly selected for the meat and fat evaluation. From each left side of them, a section of 400 725 g of longissimus thoracis muscle (m. LT) was excised at the last rib and a subcutaneous fat sample including fat layers, skin
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and lean was taken at the tail insertion in the coxal region and moved to the laboratory.
Table 2 Effect of dietary treatment on growth performance of heavy gilts. Item
a
Control
2.3. Laboratorial determinations for meat and fat samples At 8 h postmortem, colour was evaluated on subcutaneous fat and m. LT samples with a chromameter (CM 2002, Minolta Camera, Osaka, Japan), using objective measurements, as described by Latorre et al. (2009). The chromameter also provided the content in oxymyoglobin and metmyoglobin in the muscle. After measuring the colour variables, all samples were placed in individual plastic bags and vacuum-packaged at 20 1C until subsequent analyses. After 3 weeks, the samples were thawed for 24 h at 4 1C, removed from packages and blotted dry for 20 min. In the m. LT samples, moisture was determined by oven drying method (at 103 1C during 48 h) and lipids following the method proposed by Folch et al. (1957). Lipids from subcutaneous fat were extracted by the procedure developed by Bligh and Dyer (1959) and lipids of diets were extracted and quantified by Sukhija and Palmquist (1988). The FA methyl esters were analysed as described by Daza et al. (in press) using a gas chromatograph (Model HP6890, Hewlett Packard Co., Avondale, PA, USA). 2.4. Statistical analyses Data were analysed using the statistical package SAS (1999). The model included the dietary treatment as fixed effect and a covariate when was significant (the initial BW for growth performance traits and the carcass weight for carcass characteristics). Each treatment was replicated 12 times for productive performance and carcass variables (experimental unit¼the pen with 2 pigs) and 16 times for the meat and fat traits (the experimental unit¼the animal). 3. Results and discussion 3.1. Growth performance Gilts fed control diet from 100 to 130 kg BW ate 2.4% more feed (P o0.001) and tended to grow 11% faster (P¼0.08) than gilts fed barley diet (Table 2). Feeding costs were 0.03 h/kg BW more expensive (Po0.01) in pigs fed control diet than in pigs fed barley diet. The feeding costs in heavy pigs are especially important during the finishing period, and a diet based on barley would provide a cheaper feedstuff, taking into account that a possible supplementation of vitamins and minerals could be required. Recently, Daza et al. (in press) observed in gilts of BW ranging from 45 to 92 kg that the substitution of a conventional feed by a diet with barley as the only major ingredient (974.7 g kg 1) led to a reduction of ADG and an increase of ADFI and FCR. Previously, Daza et al. (2010) did not find differences for ADG and ADFI between gilts fed only granulated barley and those fed a control diet from 86 to 130 kg BW. However, FCR was worse by 13% and production costs were lower by 0.09 h/kg BW in those fed barley. These results may be due to the lack of salt, calcium and phosphate sources in the diet.
Evolution of pig BW (kg) Initial 40.0 53 days laterc 99.0 At slaughter 130.7 From 40 to 100 kg BW ADG (kg) ADFI (kg) FCR
Barley diet
SEM (n¼ 12)
Significance
41.0 100.8 129.1
0.69 0.85 1.66
NS NS NS
b
0.914 2.68 2.94
0.942 2.66 2.85
0.013 0.014 0.045
NS NS NS
From 100 to 130 kg BW ADG (kg) 0.928 ADFI (kg) 2.96 FCR 3.19
0.836 2.89 3.46
0.036 0.010 0.187
0.08
0.904 2.75 3.07 0.47
0.017 0.012 0.063 0.007
NS
From 40 to 130 kg BW ADG (kg) ADFI (kg) FCR Feeding costs (h/kg BW)
0.920 2.79 3.03 0.50
nnn
NS
n
NS nn
*P o0.05; **Po 0.01; ***Po 0.001. a BW: body weight; ADG: average daily gain; ADFI: average daily feed intake; FCR: feed conversion ratio. b Twelve pens of two pigs each per treatment. c The beginning of the experimental diets.
3.2. Carcass quality The treatments had no effect on carcass traits except for some primal cuts (Table 3); pigs fed control diet had heavier sirloin by 0.05 kg (Po0.01) and higher yield of this piece in the carcass (Po0.01) than pigs fed barley diet. Moreover, pigs fed control diet tended to have heavier loin by 0.1 kg (P¼0.07) and higher loin yield in carcass (P¼0.06) than those fed control diet. In this line, Daza et al. (in press) observed a lower loin weight in pigs fed barley from 92 to 130 kg BW than in pigs fed conventional feed, but no differences were found for ham and foreleg weights or percentage in carcass. In the current trial, the lower protein level provided by barley diet did not affect significantly the backfat depth at the level of m. GM, although it was numerically lower by 8.4% in pigs fed control diet (P¼0.14). Daza et al. (2010, in press) found similar results in heavy pigs fed mainly barley during growing–finishing periods. However, Rodriguez-Sanchez et al. (2011) observed that a reduction of dietary lysine content from 0.70 to 0.60% (from 14.5 to 14.0% of crude protein) in pigs from 100 to 130 kg BW tended to increase fat depth at m. GM by 2.4 mm. Probably, in the present work, the protein content provided in barley diet was not low enough to significantly enhance the backfat level of this muscle in this kind of pigs. When diets were formulated, a higher reduction of protein:energy ratio was planned (around 32%) in the barley diet in comparison to control diet but in the laboratorial analysis of the feeds only a 13.5% was obtained. For dry-cured ham production in Spain, the backfat depth at m. GM is one of the main requirements to select suitable carcasses at the slaughterhouse.
A. Daza et al. / Livestock Science 148 (2012) 196–200
Table 3 Effect of dietary treatment on carcass characteristics of heavy gilts. Control Barley
SEM (n¼ 12)
Significance
103.1 79.4
103.7 79.7
1.84 0.32
NS NS
85.7 38.5 77.9
85.6 38.4 77.4
0.47 0.21 0.34
NS NS NS
26.6 20.9
25.2 22.8
0.80 0.88
NS NS
Main cut weight (kg) Ham Foreleg Loin Sirloin Total a
3.5 8.3 3.2 0.44 25.4
13.4 8.4 3.1 0.39 25.3
0.08 0.07 0.05 0.01 0.38
NS NS 0.07
Main cut yield (% carcass) Ham Foreleg Loin Sirloin Total a
13.1 8.1 3.1 0.42 24.6
13.0 8.0 2.9 0.37 24.5
0.08 0.07 0.05 0.01 0.14
Carcass Weight (kg) Yield (%) Size measurements (cm) Carcass length Ham length Ham perimeter Fat depth (mm) By ultrasounds in vivo At Gluteus medius muscle postmortem
nn
NS NS NS 0.06 nn
NS
**P o 0.01. a Total ¼ hamþforeleg þ loinþ sirloin.
3.3. Meat and fat quality No effect of dietary treatment was observed on meat characteristics (data not shown). In accordance with the results of the current trial, Daza et al. (in press) reported that the replacement of conventional feed by a diet based on barley after 92 kg BW did not affect the muscle colour variables. Also, Rodriguez-Sanchez et al. (2011) observed no effect of the reduction of protein or lysine/energy ratio on colour traits. The moisture and IMF percentages obtained were 76.5 and 77.3% (P¼0.36) and 5.87 and 4.82% (P¼0.14) in control and barley pig meats, respectively. These results are in discordance with data found in other experiments which have shown an increase in IMF content of pork with a reduction of protein/energy ratio by 21% (Daza et al., in press) or 32% (Daza et al., 2010). In the current experiment, and as also noted in an explanation about backfat depth, the low reduction of protein/ energy ratio (13.5%) in the barley diet in comparison with control diet might not have been enough to increase IMF content in pigs fed barley. The lower numerical value of IMF percentage observed in meat from gilts fed barley in the present work (4.82 vs. 5.87%) could be due, at least in part, to the lack of vitamin and mineral premix in that diet, especially vitamin A. The effect of dietary vitamin A on IMF content is controversial and there is limited information on this topic in swine. D’Souza et al. (2003) found a higher IMF content in loin from lean pigs when vitamin A was completely removed from the vitamin– mineral complex, whereas Olivares et al. (2009a) observed no effect of vitamin A in a similar situation.
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Based on the inhibitory effect of retinoids in cultured preadipocyte differentiation (Brandebourg and Hu, 2005), it has been proposed that the effect of vitamin A level on IMF is mediated by adipocyte differentiation (Dimaculangan et al., 1994). In the current experiment, that cell differentiation had to be occurred before the replacement of finishing conventional diet by granulated barley when no vitamin A was provided. No differences were detected between treatments in the major FA proportions of the subcutaneous fat (data not shown) suggesting that the lower crude protein content and the lack of vitamin–mineral complex in the barley diet in comparison to the control had scarce effect on FA composition of pigs. These results agree with data from Daza et al. (in press). Also, Olivares et al. (2009b) did not detect any influence of dietary vitamin A level in finishing diet on FA pattern of subcutaneous backfat outer and inner layers. It is important to note that C18:2 content in subcutaneous fat was around 10% in pigs fed both diets which is positive because a higher value than 12% is not recommended for transformation and conservation processes of meat (Wood et al., 2008). The diet only had a clear effect on C17:0 of IMF from m. LT which was higher in control than in barley gilts (Po0.05) which agrees with data from Daza et al. (2010). In the current study, the control diet, that included higher vitamin A level, showed a tendency to increase total saturated FA (P¼0.16) and decreased total monounsaturated FA (P¼0.15) proportions, but no influence on total polyunsaturated FA proportion was observed. The desaturation indexes C16:1n-7/C16:0, C18:1n-9/C18:0 and monounsaturated FA/saturated FA were lower in control than in barley gilts. Olivares et al. (2009b) reported that the dietary vitamin A increased significantly saturated FA and decreased monounsaturated FA in IMF from fatty pigs and, as in our experiment, no significant effect on polyunsaturated FA was found. 4. Conclusion It is concluded that in finishing production of gilts intended for dry-cured products, replacement of a conventional feed with granulated barley could reduce feed intake and feed costs, without causing effect on carcass, meat and fat traits of pigs, except a reduced weight of the sirloin. Conflict of interest statement No conflict of interest has influenced the development of the work titled: ‘‘Effect of replacement of a conventional diet by granulated barley during finishing period on growth performance and carcass and meat characteristics in 130kg gilts’’.
Acknowledgements This research was supported by Project PET-200708C11-05 (INIA).
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