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The effects of male and female immunocastration on growth performances and carcass and meat quality of pigs intended for dry-cured ham production: A preliminary study
Livestock Science 190 (2016) 20–26
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The effects of male and female immunocastration on growth performances and carcass and meat quality of pigs intended for dry-cured ham production: A preliminary study A. Daza a, M.A. Latorre b,n, A. Olivares c, C.J. López Bote c a Departamento de Producción Animal, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad Politécnica, Ciudad Universitaria, 28040 Madrid, Spain b Facultad de Veterinaria, Universidad de Zaragoza, C/Miguel Servet 177, 50013 Zaragoza, Spain c Departamento de Producción Animal, Facultad de Veterinaria, Universidad Complutense, Ciudad Universitaria, 28040 Madrid, Spain
art ic l e i nf o
a b s t r a c t
Article history: Received 9 December 2015 Received in revised form 18 May 2016 Accepted 26 May 2016
A total of 48 Duroc (Landrace Large White) pigs, 24 males and 24 females, with 8573 d of age were used to study the effect of sex and immunocastration on growth performances and carcass and pork quality. There were 4 experimental treatments; surgical castrated males (SCM), immunocastrated males (ICM), entire females (EF) and immunocastrated females (ICF). The surgical castration had been carried out in 12 males when were 5 73 d of age. The immunocastration consisted in two vaccinations with Improvacs, in 12 boars and in 12 gilts, at the beginning of the trial and 28 d later (45.4 and 70.6 kg body weight as average, respectively). Pigs were intended for dry-cured ham elaboration; therefore, heavy body weight (126 kg and 167 d of age as average) and a minimum of carcass fat depth (20 mm) were required. During the overall period (from days 0–82), SCM were less efficient converting feed into gain than the rest of the treatments (P ¼0.049). At slaughter, ICM were heavier than SCM and ICF with EF being intermediate (P ¼0.05) and ICF were fatter, as much at 10th rib (P¼ 0.05) as at level of Gluteus medius muscle (P ¼0.043), than EF with males (SCM and ICM) in an intermediate position. As a consequence, EF had the leanest carcasses (P ¼0.048) and 25% of them were rejected for lack of fatness vs 0% in the other treatments (P¼ 0.02). Pork from ICF was redder (higher a*) than that from ICM (P o0.001) and meat from SCM showed a more intense color (higher C*) (P ¼0.03) and tended to have lower level of oxymyoglobin (P ¼0.061) and metmyoglobin (P ¼0.082) than that from EF. The intramuscular fat content was not affected. The inmunocastration of males or females had limited influence on major fatty acids of subcutaneous or intramuscular fat. It can be concluded that immunocastration could be interesting in pigs intended for dry-cured ham elaboration because in males improved the feed conversion ratio with no penalization of carcass or meat quality, in comparison to surgical castration, and in gilts increased backfat thickness of carcass reducing to 0% the rejections at slaughterhouse for lack of fatness. & 2016 Elsevier B.V. All rights reserved.
Keywords: Pig immunocastration Sex Growth performances Carcass fatness Meat
1. Introduction In Spain, the dry-cured ham industry requires a minimum of carcass weight (86 kg) and of fat thickness over the Gluteus medius muscle (m. GM; 20 mm) and a maximum of C18:2n-6 proportion in subcutaneous fat (12% and 15% in fresh and cured pieces, respectively) to guarantee the adequate processing and end quality (Daza et al., 2012). Taking into account these considerations, some studies have concluded that barrows would be preferred to gilts for that aim (Peinado et al., 2008, 2011). In fact, Latorre et al. (2008, 2009) detected that around 30% of carcasses were rejected n
Corresponding author. E-mail address: [email protected] (M.A. Latorre).
http://dx.doi.org/10.1016/j.livsci.2016.05.014 1871-1413/& 2016 Elsevier B.V. All rights reserved.
at slaughterhouse, mainly due to the lack of fatness, being all gilts. Moreover, it has been demonstrated that pork from barrows has higher intramuscular fat content than that from gilts (RodríguezSánchez et al., 2011, 2014) which is desirable because of its beneficial effects on eating quality (Fernández et al., 1999). For all of that, strategies to increase backfat thickness and intramuscular fat proportion in gilts are being studied such as the surgical castration. This method of castration has been practiced in males for centuries to prevent the boar taint and aggressive behavior with higher body fatness as a collateral effect (Barton Gade, 1987; Meier-Dinkel et al., 2015). In females, a similar impact in fatness has been observed (Peinado et al., 2011, 2012). However, currently in Spain, surgical castration is only permitted in males, with a plan to voluntarily end it in the EU in 2018 by animal
A. Daza et al. / Livestock Science 190 (2016) 20–26
welfare reasons (PIGCAS, 2009), and exceptionally in females, when are reared outdoor to avoid pregnancies by wild boars, using prolonged analgesia and anesthesia (Boletín Oficial Estado, 2009). In this context, the immunocastration is being evaluated as possible substitute to physical castration. Its effects in males have been widely studied (Pauly et al., 2009; Fábrega et al., 2010; Gispert et al., 2010; Morales et al., 2011; Font i Furnols et al., 2012, 2016), with some controversial results, but the information about its use in females is really limited and focused in autochthonous breeds. So Gómez-Fernández et al. (2013) concluded that the immunocastration could be an interesting economical alternative, in Iberian gilts, to the surgical castration because improved growth performances and had a clear positive influence on pig welfare. Daza et al. (2014) carried out a small trial using commercial gilts with no conclusive results. Although it reported that immunocastration increased fatness, the slaughter was carried out with different BW (130 and 124 kg for immunocastrated and intact females, respectively) which could have affected those variables. The objective of the present experiment was to evaluate the effects of immunocastration of males and females in productive performances and carcass and meat quality when are intended for elaboration of dry-cured ham.
2. Material and methods 2.1. Animal husbandry and feeding All the experimental procedures used in the trial were in compliance with the Spanish guidelines for the care and use of animals in research (Boletín Oficial Estado, 2007). A total of 48 Duroc (Landrace Large White) pigs, 24 males and 24 females, with 8573 d of age (46.3 and 42.9 kg of body weight (BW), respectively) were used. All of them came from the same farm where they had previously had the same feeding and management. On arrival at the experimental facilities (El Chantre, Teruel, Spain), pigs were individually weighed, housed in a controlled environment barn and randomly allotted to 16 pens (2.30 m 2.6 m and 30% slotted floor) of three animals each, according to the sex and BW. The study was conducted as a completely randomized design that included four experimental treatments according to the pig sex or method of castration: surgical castrated males (SCM), immunocastrated males (ICM), entire females (EF) and immunocastrated females (ICF). The surgical castration had been previously done in the origin farm in 12 males with 5 73 d of age. The immunocastration consisted in two vaccines against GnRH with Improvacs (Zoetis, Madrid, Spain) and was carried out in 12 males and 12 gilts following the recommendations of the company; at days 0 and 28 of the trial (with 45.4 and 70.6 kg BW as average, respectively). The feeding program was common for all pigs consisting in a commercial diet that included (per kg of feed): 537 g barley, 200 g wheat, 130 g rapeseed meal, 40 g sunflower meal, 40 g wheat flour, 12.5 g blended fat, 10.0 g molasses sugarcane, 13.3% calcium carbonate, 2.7 g dicalcium phosphate, 4.5 g sodium chloride, 0.6 g L-lysine 50%, 0.6 g DL-methionine 99%, 6.6 g L-threonine and 2.0 g vitamin and mineral premix. The estimated energy content (FEDNA, 2010) and the analysed nutritional composition of diet is shown in Table 1. Pigs had ad libitum access to pelleted diet, in a single space feeder, and water throughout the trial and were slaughtered on the same day with 16773 d of age (126 kg BW as average). 2.2. Growth performances Individual BW was recorded at day 0 (beginning of the trial and 1st Improvac vaccine), day 28 (2nd Improvac vaccine), day 63 and
21
Table 1 Nutrient composition of the diet used in the trial for pigs from 85 to 167 d of age. g/kg, as-fed basis Calculated analysisa Digestible energy (MJ/kg) 13.74 Determined analysis Dry matter Crude protein (N 6.25) Crude fiber Crude fat
883.3 139.1 51.3 32.1
Fatty acids C14:0 C16:0 C18:0 C18:1n-9 C18:2n-6 C18:3n-3
0.29 4.14 1.31 4.98 16.34 2.99
a
According to FEDNA (2010).
day 82 (end of the trial) to calculate average daily gain (ADG). The average daily feed intake (ADFI) was calculated per pen, for the periods 0–28, 28–63, 63–82 and 0–82 d of the trial, taking into account the feed given and the orts. After, the data of ADG and ADFI per pen were used to calculate the feed conversion ratio (FCR) for the same periods. In addition, data of fat thickness (in mm) were taken at days 28, 63 and 82 of the trial using ultrasound RTU equipment (Kretz Technick Inc, 600V-V2.232, Sonovet, Austria). After a previous calibration according to manufacturer recommendations, measures were recorded by the same operator, on the right side of all animals, at last rib level, over the skin without clipping the hair. 2.3. Slaughter, carcass measures and sampling The day before slaughter, feed was withdrawn 8 h and pigs were transported to a commercial abattoir (35 min transport time) using a single-decked trailer, equipped with upper hydraulic floor, with capacity for 120 pigs distributed into 8 separate compartments. The truck was driven with the 80 experimental pigs being distributed into 4 compartments only (loading density of 0.56 m2/pig). Pigs belonging to the same treatment were allotted to the same box. At the slaughterhouse, animals were kept in lairage for 10 h, with full access to water but not to feed, and after they were electrically stunned (225–380 V/0.5 A for 5–6 s), exsanguinated, scalded, skinned, eviscerated, and split down the midline according to standard commercial procedures. The following measures were individually taken from all carcasses (12 per treatment). Hot carcass weight was recorded to calculate dressing percentage. At 45 min postmortem, carcass length (from the posterior edge of the Symphysis pubis to the anterior edge of the first rib), ham length (from the anterior edge of the Symphysis pubis to the hock joint) and ham perimeter (at its widest side) were measured on the left carcass side by a tape of centimeter precision. Carcass compactness was then calculated as carcass weight/carcass length. In addition, on the same carcass side, backfat thickness was measured at the level of the 10th rib and over the m. GM (skin included) using a rule of millimeter precision. The proportion of rejected carcasses was calculated using the fat thickness at m. GM (o20 mm) as the criterion. The percentage of lean in carcass was estimated according to ZP method (Diario Oficial Unión Europea, 2012) by the following equation: lean proportion (%)¼58.89–0.821F-ZPþ 0.157 M-ZP where F-ZP was the fat depth at m. GM and M-ZP was the shortest connection between the front (cranial) end of the m. GM and the upper (dorsal) edge of the vertebral canal measured also by rule.
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A. Daza et al. / Livestock Science 190 (2016) 20–26
After refrigeration at 2 °C (1 m/s air speed; 90% relative humidity) for 6 h, carcasses were processed according to commercial standards. The ham and shoulder from the left side of each carcass were trimmed, to fit commercial requirements, and individually weighed to calculate their yield. After processing, from all carcasses, a section of 500 720 g of Longissimus thoracis muscle was excised at the level of the last rib from the left loin. A subcutaneous fat sample (607 4 g), including fat layers, skin and lean was also taken from each carcass at the tail insertion in the coxal region. From each meat sample, one 2-cm-thick slice was taken for measuring color and the rest, as well as the fat samples, were vacuum-packaged in individual bags and stored at 20 °C until subsequent analyses. 2.4. Laboratorial analyses The fresh slices were displayed on polystyrene trays, overwrapped with oxygen–permeable polyvinyl chloride wrap and stored at 4 °C during 3 d. Color stability was assessed by measurements days 1, 2 and 3 of display in air at 4 °C, after blooming for 1 h, using a chromameter (Model CM 2002; Minolta Camera, Osaka, Japan), with illuminant D65 and 10° standard observer. The average of three random readings was used to measure: lightness (L*), redness (a*) and yellowness (b*) (Commission internationale de l’Eclairage, 1976). Additionally, chroma (C*) was calculated as C* ¼√(a*2þb*2) which is related to the quantity of pigments (Wyszecki and Stiles, 1982). Also, the three myoglobin species were calculated as ratios of measurements at then given wavelengths; deoxymyoglobin (dMb; 473 nm/525 nm), oxymyoglobin (oMb; 610 nm/525 nm) and metmyoglobin (metMb; 572 nm/ 525 nm). Chemical analysis of feed for dry matter (930.15), crude protein (984.13) and crude fiber (978.10) was carried out according to AOAC (2005) procedures. The fatty acids of the diet were extracted and quantified by the one-step procedure described by Sukhija et al. (1988) in lyophilized samples. Pentadecenoic acid (C15:1) (Sigma, Alcobendas, Madrid, Spain) was used as internal standard. Previously, methylated fatty acid samples were identified according to Rey et al. (1997) using a gas chromatograph (Model HP6890; Hewlett Packard Co., Avondale, PA, USA) and a 30 m 0.32 mm 0.25 mm cross-linked polyethylene glycol capillary column (Hewlett Packard Innowax, Avondale, PA, USA). A temperature program of 170–245 °C was used. The injector and detector were maintained at 250 °C. The carrier gas (helium) flow rate was 3 mL/min. Lipids from subcutaneous fat (outer and inner layers separately) were extracted by the procedure proposed by Bligh et al. (1959) while lipids from intramuscular fat were obtained according to the method developed by Marmer et al. (1981). Fat extracts were methylated in the presence of sulphuric acid and analysed as described above. The proportion of total saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids were calculated from individual fatty acid percentages.
was used to evaluate the normal distribution of data using the transformation arc sin (x/100)0.5 for those whose distribution was not normal (ham and shoulder yields, as well as percentage of rejected carcasses because of low fatness). A P-value of r 0.05 was considered as a significant difference between treatments and a Pvalue between 0.05 and 0.10 as a trend.
3. Results 3.1. Growth performances The effect of immnocastration on males and females on productive performances is shown in Table 2. From days 0 (1st vaccination) to 28 of the trial, EF grew faster than ICF with the groups of males (SCM and ICM) being intermediate (P ¼0.005). In addition, EF tended (P ¼0.09) to eat more and ICF tended (P¼ 0.09) to be less efficient converting feed into gain than the other treatments. From days 28 (2nd vaccination) to 63 and also from days 63–82 of the study (slaughter), no significant effect was detected for the growth performance traits evaluated. During the overall period (from days 0 to 82), SCM had higher FCR than the rest of the treatments (P ¼0.049). Therefore, at slaughter, ICM were heavier than SCM and ICF with EF being intermediate (P ¼0.05). Also, ICF
Table 2 Growth performances and fat depth in vivo measurements of surgical castrated males (SCM), immunocastrated males (ICM), entire females (EF) and immunocastrated females (ICF) intended for dry-cured ham production. Variablea
ICM
EF
45.0
47.6
42.7
70.2xy
69.1yz
72.1x
104.9 124.3y
106.7 131.0x
109.3 126.7xy
From 0 to 28 d of trial ADG (kg/d) ADFI (kg/d) FCR
0.912xy 2.27 2.48
0.874yz 2.20 2.47
0.981x 2.33 2.42
0.806z 0.028 2.20 1.072 2.78 0.101
0.005 0.09 0.09
From 28 to 63 d of trial ADG (kg/d) ADFI (kg/d) FCR
0.990 3.00 3.06
1.050 3.00 2.86
1.070 2.94 2.74
1.030 3.65 2.85
0.033 0.363 0.102
0.34 0.49 0.22
From 63 to 82 d of trial ADG (kg/d) ADFI (kg/d) FCR
1.120 4.03 3.64
1.230 4.03 3.34
1.150 3.93 3.43
1.440 4.02 2.90
0.114 0.051 0.231
0.20 0.47 0.19
From 0 to 82 d of trial ADG (kg/d) ADFI (kg/d) FCR
0.993 2.97 2.99x
1.040 2.96 2.75y
1.050 2.92 2.84y
1.030 2.90 2.85y
0.203 0.035 0.051
0.18 0.44 0.049
10.0 15.1 22.3xy
10.6 15.5 22.4xy
10.0 14.7 20.7y
0.63 0.46 0.67
0.60 0.44 0.05
BW, kg At day 0 (vaccination 1) At day 28 (vaccination 2) At day 63 At day 82 (slaughter)
2.5. Statistical analyses Data were analysed using the statistical package SPSS-16. The model included the pig sex or method of castration (SCM, ICM, EF and ICF) as main effect and the initial BW as covariate for productive performances when was significant. Duncan's test was used to assess differences between treatment means. In order to estimate the relationships between oMb/metMb ratio and ageing (days), regression analysis was carried out. Each treatment was replicated 4 times for growth performance traits (experimental unit ¼pen with 3 pigs each) and 12 times for carcass, meat and fat variables (experimental unit ¼animal). Shaphiro et al. (1965) test
SCM
Fat depth (mm) At day 28 At day 63 At day 82 (slaughter) a
ICF
SEM (n ¼4)
P-value
43.2
1.25
0.06
67.2z
0.80
0.005
102.9 125.7y
1.82 1.60
0.10 0.05
9.3 14.5 23.1x
BW: body weight; ADG: average daily gain; ADFI: average daily feed intake; FCR: feed conversion ratio. x,y,z Within a row, means without a common superscript letter differ (Po 0.05).
A. Daza et al. / Livestock Science 190 (2016) 20–26
effects (Table 4). Pork from ICF was redder than that from ICM with SCM and EF in intermediate positions (Po 0.001). Also, meat from SCM showed a more intense color (higher C*) (P ¼0.03) and tended to have lower contents in oMB (P¼ 0.061) and in metMb (P ¼0.082) than that from EF with immunocastrated pigs (ICM and ICF) being intermediate. Loin from ICF showed lower oMb/metMb ratio than the other treatments (P ¼0.001). The intramuscular fat content was not affected by the experimental treatment. With respect to ageing, the redness (P ¼0.01) and chroma (P o0.001) were higher at days 1 and 2 than at day 3. Also, the yellowness decreased in the order day 1 42 43 (Po 0.001), whereas the oMB level (P o0.04) and oMb/metMb ratio (P ¼0.001) increased in the opposite way (day 3 42 4 1).
Table 3 Carcass characteristics of surgical castrated males (SCM), immunocastrated males (ICM), entire females (EF) and immunocastrated females (ICF) intended for drycured ham production.
Carcass weight (kg) Carcass yield (%) Carcass length (cm) Ham length (cm) Ham perimeter (cm) Carcass compactnessa Backfat thickness (mm) At 10th rib At Gluteus medius muscle Carcass rejected (%)b Lean yield (%)c
SCM
ICM
EF
ICF
SEM (n ¼ 12)
P-value
95.8 77.1 88.4 41.0 74.8 1.08
100.6 76.9 90.8 41.0 73.4 1.11
98.8 77.0 88.6 40.5 76.0 1.12
97.2 75.9 88.2 39.9 75.7 1.10
2.35 0.56 0.84 0.54 0.77 0.020
0.52 0.42 0.12 0.48 0.92 0.70
27.7xy 21.3xy
28.0xy 22.4xy
25.2y 28.3x 1.03 20.2y 23.6x 0.91
0.05 0.043
0y 52.3xy
0y 51.1xy
25x 0y 6.68 53.2x 50.0y 0.90
0.025 0.048
14.6 8.06 22.6
14.0 8.06 22.0
14.5 8.01 22.5
0.065 0.17 0.12
23
3.4. Fatty acid profile of subcutaneous and intramuscular fat
Carcass weight (kg)/carcass length (cm). Carcasses which did not fulfill the minimum required backfat thickness at Gluteus medius muscle (20 mm). c Calculated according to ZP method (Diario Oficial Unión Europea, 2012). d Ham þ shoulder from half a carcass. x,y Within a row, means without a common superscript letter differ (Po 0.05).
The inmunocastration of males or females had limited influence on major fatty acids of outer and inner subcutaneous backfat layers (Table 5). Only, the C18:1n-9 proportion of outer backfat was affected being lower in ICM than in the groups of females (EF and ICF) with SCM being intermediate (P o0.05). Similarly, in the fatty acid profile of intramuscular fat, no differences were observed. In addition, the total SFA, MUFA and PUFA, the sum of n-6 and n-3, and also the C16:1n-6/C16:0, C18:1n-9/C18:0, MUFA/ SFA, PUFA/SFA and n-6/n-3 ratios in both types of fat (subcutaneous and intramuscular) were not affected by experimental treatments (data not shown).
had wider backfat thickness, measured in vivo, than EF with both groups of males in an intermediate position (P ¼0.05).
4. Discussion
Yield main cuts (% carcass) Ham Shoulder Totald
14.3 7.84 22.2
0.16 0.076 0.19
a
b
3.2. Carcass quality
It has to be noted that this was a preliminary study and the number of replicates per treatment was limited.
The inmunocastration had no effect on carcass yield or ham size (Table 3). However, the ICF was fatter, measured at 10th rib (P¼0.05) and at m. GM (P¼ 0.043), than EF with males (SCM and ICM) being intermediate. As a consequence, EF had the leanest carcasses (P¼0.048) and 25% of them were rejected for lack of fatness (P¼0.02). Also, SCM and EF tended (P¼ 0.065) to show higher ham yield than immunocastrated animals (males and females).
4.1. Growth performances The information about immunocastration in gilts is very scarce which complicates in part the present discussion. In the current trial, from the 1st to the 2nd injection, ICF grew slower and tended to eat less feed and to be less efficient converting feed into gain than EF. However, no difference was detected between SCM and ICM. It suggests that the effect of the 1st Improvac vaccination had different effects in both sexes with no influence in males but impairing the growth productive traits in gilts. In males, Morales et al. (2011, 2013) found that ICM had lower ADFI and ADG
3.3. Meat characteristics No significant interaction was detected between sex and ageing for meat characteristics; therefore, results are shown by main
Table 4 Meat characteristics of surgical castrated males (SCM), immunocastrated males (ICM), entire females (EF) and immunocastrated females (ICF) intended for dry-cured ham production. Sex
Color traits Lightness, L* Redness, a* Yellowness, b* Chroma, C* Myoglobin speciesa dMb oMb metMb oMb/metMb Intramuscular fat (%) a
Ageing (d)
P-value
SCM
ICM
EF
ICF
SEM (n ¼12)
1
2
3
SEM (n¼ 48)
Sex
Ageing
Sex ageing
55.0 3.14y 13.9 14.4x
54.6 2.25z 13.2 13.4yz
52.8 2.63yz 13.0 13.3z
53.9 4.21x 13.5 14.2xy
0.82 0.23 0.30 0.31
54.9 3.23x 14.2x 14.7x
54.3 3.38x 13.4y 13.9x
53.1 2.57y 12.6z 12.9y
0.71 0.20 0.26 0.27
0.21 o 0.001 0.11 0.03
0.22 0.01 o 0.001 o 0.001
0.69 0.74 0.64 0.63
1.06 3.71 7.71 0.50x 5.24
1.05 4.53 8.88 0.51x 4.22
1.06 5.71 10.8 0.52x 4.33
1.06 4.66 10.6 0.45y 4.59
0.008 0.53 0.99 0.012 0.382
1.09x 3.99y 9.19 0.43z –
1.04z 4.38xy 9.13 0.48y –
1.06y 5.59x 10.2 0.56x –
0.007 0.46 0.86 0.010 –
0.57 0.06 0.08 0.001 0.25
o 0.001 o 0.04 0.63 0.001 –
0.83 0.78 0.65 0.34 –
dMb: deoxymyoglobin (at 473 nm/525 nm); oMb: oxymyoglobin (at 610 nm/525 nm); metMb: metmyoglobin (at 572 nm/525 nm). Within a row, means without a common superscript letter differ (P o 0.05).
x,y,z
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A. Daza et al. / Livestock Science 190 (2016) 20–26
Table 5 Major fatty acids of subcutaneous and intramuscular fat from surgical castrated males (SCM), immunocastrated males (ICM), entire females (EF) and immunocastrated females (ICF) intended for dry-cured ham production. % of total fatty acids SCM
ICM
EF
ICF
SEM (n¼ 12) P-value
Subcutaneous fat
Outer layer C16:0 C18:0 C18:1n-9 C18:2n-6
23.38 14.88 39.35xy 11.82
23.48 23.28 23.29 15.22 15.00 15.43 38.63y 39.44x 39.81x 11.97 11.59 11.36
0.201 0.253 0.282 0.302
0.88 0.42 o 0.05 0.54
Inner layer C16:0 C18:0 C18:1n-9 C18:2n-6
24.82 17.40 37.62 10.32
24.52 17.15 38.02 10.51
24.49 17.02 38.38 10.45
24.31 17.28 38.62 10.10
0.192 0.271 0.313 0.284
0.28 0.76 0.15 0.74
Intramuscular fat C16:0 C18:0 C18:1n-9 C18:2n-6
24.62 14.72 41.63 7.26
24.38 14.97 41.02 7.61
24.62 14.20 42.15 7.17
24.46 14.53 42.09 7.28
0.224 0.245 0.423 0.262
0.82 0.16 0.22 0.65
x,y
Within a row, means without a common superscript letter differ (Po 0.05).
compared to SCM with similar FCR. Authors justified it by the stress of the injection (Fábrega et al., 2010) and an increase of the body temperature (Pauly et al., 2009). In the case of females, in a preliminary study, Daza et al. (2014) did not find significant differences between EF and ICF. From the 2nd Improvac vaccination to the slaughter, in the current experiment, ICM had 8% better FCR than SCM but it was not statistically significant which is in agreement with the results of Metz et al. (2002). However, taking into account the most of literature papers, better growth performances were expected in ICM than in SCM and we do not have an explanation for it. In fact, in a meta-analysis that included 41 experiments, Batorek et al. (2012) found that ICM displayed higher ADFI and ADG and better FCR than SCM attributing it to a reduction of steroidogenic capacity (Dunshea, 2010) and to a quick decrease of testosterone concentration after the injection (Zamaratskaia et al., 2008). With respect to females, the FCR was similar (2.98 vs 2.86 for EF and ICF, respectively) which agrees with the work of Daza et al. (2014) evaluating gilts of the same crossbred and similar slaughter BW. For the overall period, the SCM had higher FCR than ICM, EF and ICF (by 8.7%, 5.3% and 4.9%, respectively). Morales et al. (2011) also detected better FCR in ICM than in SCM from 31 to 123 kg BW. After, Morales et al. (2013) compared SCM, ICM and EF from 42 to 125 kg BW observing better feed efficiency in ICM than in the other treatments. The groups of females (EF and ICF) had similar growth performance results, in agreement with the preliminary study of Daza et al. (2014). The discrepancies among experiments might be related to differences in the pig genetic crossbred as well as to aspects relative to the Improvac use (i.e. age at vaccinations or number of injections). 4.2. Carcass quality Results of backfat depth in carcass measured by rule confirmed data recorded by ultrasounds in in vivo animals just before slaughter. It is widely accepted that surgical castration of males increased carcass fatness compared to boars (Nold et al., 1997; Weatherup et al., 1998). Suster et al. (2006) explained the increased lipolysis and the decreased muscle accretion in SCM by a reduced production of growth hormone and IGF-1. However, comparing SCM and ICM, literature is more controversial. Dunshea
et al. (2001) found higher backfat depth in SCM and similar results were detected by Morales et al. (2011, 2013) who also measured lean percentage being lower in SCM. However, in the current trial, no effect of immunocastration was detected in this sense. Zeng et al. (2002) evaluated SCM and IMC vaccinated at 70 and 119 d of age and slaughtered at 161 d of age and 110 kg of BW with similar finds. The available data suggest that carcass quality of ICM is influenced by two main factors: the growth potential of the boars before the second vaccination and the time interval elapsed between the second vaccination and slaughter (Dunshea et al., 2001; Metz et al., 2002). In the current study, irrespectively of method of castration, all males produced fattier carcasses than the minimum required for dry-cured ham elaboration. In the case of SCM, it was expected because Latorre et al. (2008, 2009) reported similar results but, in the case of ICM, which were more unpredictable, they can be considered very positive. The immunocastration was very effective increasing backfat thickness in females, and then the lean yield was higher in EF than in ICF, which agrees with results of Oliver et al. (2003) and Daza et al. (2014). Other authors (Serrano et al., 2008; Peinado et al., 2011) have also found that the gilt surgical castration increased carcass fatness in comparison to EF. As a consequence of the results of fat depth at m. GM, the proportion of carcasses rejected at slaughterhouse from ICF was 0% whereas from EF was 25% which is a success of the immunocastration. The percentage of rejects in EF confirms the results of Latorre et al. (2008, 2009) who quantified it in almost 30%. Other positive effect of immunocastration in females was that ham or shoulder yield was not penalized, in agreement with data of Gómez-Fernández et al. (2013). Those authors observed, in Iberian gilts slaughtered at 160 kg BW, similar weight of these major pieces in EF and ICF being, in both cases, higher than in surgical castrated females which would confirm the higher fatness of physically castrated females. 4.3. Meat characteristics Meat color is a sensorial trait that has an important influence on consumers to choose pork products. Several studies did not find any significant effect on pork color of the surgical castration in males (Barton-Gade, 1987; Weatherup et al., 1998) and in females (Serrano et al., 2008; Peinado et al., 2008, 2011) in comparison to entire animals. In the present study, the loin from SCM had higher a* and C* values than that from ICM indicating a more intense color in pork from the first ones. Lowe et al. (2014), fourteen days after slaughter, also observed that SCM had redder and more yellow pork than ICM. In females, the immunocastration provided higher a* and C* values in meat whereas Daza et al. (2014) did not detect any effect. Comparing immunocastrated animals, meat from ICF was redder than that from ICM. Several factors can have influence on color pork such as the management of animals during transportation and at abattoir, the slaughter method and the conditions of data collection (Mancini and Hunt, 2005). There are few studies about the effect of ageing on color stability of pork. The three myoglobin species found in fresh meat (dMb, oMb and metMb, related to purple, bright red or brown color, respectively) have different reflectance spectra and hence different colors, and tristimulus color parameters (L*, a* and b* values) are shown to vary according to the myoglobin species. The evolution of redness, yellowness, intensity of color (C*) and oMb showed a clear discoloration as time goes. In fact, a linear regression equation was obtained between oMb/metMb ratio and time: oMb/metMb ¼0.367þ0.0633 ageing (in days) (R2 ¼0.47; Po 0.001) indicating a higher ratio from days 1 to 3. Our results confirm those of Rosenvold et al. (2003) and also those of Lindahl et al. (2006) who evaluated color variables through 9 d of aerobic storage.
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There was no significant difference among treatments in intramuscular fat content although it was 24% higher in SCM than in ICM and 6% higher in ICF than in EF. The lack of differences between SCM and ICM is consistent with results of Gispert et al. (2010), Font i Furnols et al. (2012) and Morales et al. (2013). Daza et al. (2014) neither found differences between ICF and EF in this variable. 4.4. Fatty acid profile of subcutaneous and intramuscular fat Limited differences were observed among treatments in the fatty acid profile of fat. Only C18:1n-9 proportion of the outer layer of subcutaneous fat was higher in females (EF and ICF) than in ICM being SCM intermediate. In general, the practice of surgical castration increases body fatness and then SFA also increases as much in males (Mackay et al., 2013) as in females (Serrano et al., 2008; Peinado et al., 2011). The main fatty acids produced from de novo synthesis are the palmitic and stearic; therefore, as pigs continue depositing fatty acids and adipocytes fill with triglycerides from de novo synthesis, the proportion of SFA in adipose tissue is increased (Wood et al., 2008). About immunocastration of males, our lack of differences agree with the study of Font i Furnols et al. (2012) but Tavárez et al. (2014) found higher PUFA in belly adipose tissue of ICM than in that of SCM. Also, Mackay et al. (2013) detected higher ∑n-6 in ICM explaining it by changes in lipogenic enzyme protein expression. In females, some authors observed higher PUFA in ICF than in EF (Gamero-Negrón et al., 2015) whereas others (Daza et al., 2014) reported in ICF higher C16:0, C18:0 and SFA and lower C18:1n-9 and MUFA and C18:2n-6 and PUFA proportions in subcutaneous backfat and intramuscular fat of loin. The reasons for the lack of effects in the current trial could be the small differences in backfat depth (2–3 mm), being lower than in other trials and even no influence was observed in the intramuscular fat content. In fact, Wood et al. (2008) reported that at least 4 mm of difference are required to detect changes in the fatty acid profile. Moreover, in the current work, the time elapsed from the second vaccination to slaughter (54 d) could not be enough to modify fat composition according to the work of Asmus et al. (2014).
5. Conclusions Under our experimental conditions, it can be concluded that the immunocastration in males improved feed conversion ratio and did not decrease carcass fatness, in comparison to those physically castrated, which is positive in pigs intended for drycured ham elaboration. In females, the immunization against GnRH did not penalize growth performances and increased fat depth at m. GM which carried out no carcass rejection at slaughterhouse. Finally, the use of Improvacs had limited effect on pork quality and fatty acid profile but it seems increasing the homogeneity between sexes (males and females) in terms of productive performance and quality.
Acknowledgements This research was supported by Project PET-2007-08C11-05 (INIA). Thanks to E. Feliz de Vargas and I. Garitano (El Chantre, Teruel, Spain) for the control of animals and to L. Ariño (Jamones y Embutidos Alto Mijares S. L., Teruel, Spain) for the help during the slaughter and sampling. References AOAC, 2005. Horwitz, W., Latimer, G.W. (Eds.), Official methods of analysis, 18th ed. Association of Official Analytical Chemists, Gaithersburg, MA.
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The effects of male and female immunocastration on growth performances and carcass and meat quality of pigs intended for dry-cured ham production: A preliminary study A. Daza a, M.A. Latorre b,n, A. Olivares c, C.J. López Bote c a Departamento de Producción Animal, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad Politécnica, Ciudad Universitaria, 28040 Madrid, Spain b Facultad de Veterinaria, Universidad de Zaragoza, C/Miguel Servet 177, 50013 Zaragoza, Spain c Departamento de Producción Animal, Facultad de Veterinaria, Universidad Complutense, Ciudad Universitaria, 28040 Madrid, Spain
art ic l e i nf o
a b s t r a c t
Article history: Received 9 December 2015 Received in revised form 18 May 2016 Accepted 26 May 2016
A total of 48 Duroc (Landrace Large White) pigs, 24 males and 24 females, with 8573 d of age were used to study the effect of sex and immunocastration on growth performances and carcass and pork quality. There were 4 experimental treatments; surgical castrated males (SCM), immunocastrated males (ICM), entire females (EF) and immunocastrated females (ICF). The surgical castration had been carried out in 12 males when were 5 73 d of age. The immunocastration consisted in two vaccinations with Improvacs, in 12 boars and in 12 gilts, at the beginning of the trial and 28 d later (45.4 and 70.6 kg body weight as average, respectively). Pigs were intended for dry-cured ham elaboration; therefore, heavy body weight (126 kg and 167 d of age as average) and a minimum of carcass fat depth (20 mm) were required. During the overall period (from days 0–82), SCM were less efficient converting feed into gain than the rest of the treatments (P ¼0.049). At slaughter, ICM were heavier than SCM and ICF with EF being intermediate (P ¼0.05) and ICF were fatter, as much at 10th rib (P¼ 0.05) as at level of Gluteus medius muscle (P ¼0.043), than EF with males (SCM and ICM) in an intermediate position. As a consequence, EF had the leanest carcasses (P ¼0.048) and 25% of them were rejected for lack of fatness vs 0% in the other treatments (P¼ 0.02). Pork from ICF was redder (higher a*) than that from ICM (P o0.001) and meat from SCM showed a more intense color (higher C*) (P ¼0.03) and tended to have lower level of oxymyoglobin (P ¼0.061) and metmyoglobin (P ¼0.082) than that from EF. The intramuscular fat content was not affected. The inmunocastration of males or females had limited influence on major fatty acids of subcutaneous or intramuscular fat. It can be concluded that immunocastration could be interesting in pigs intended for dry-cured ham elaboration because in males improved the feed conversion ratio with no penalization of carcass or meat quality, in comparison to surgical castration, and in gilts increased backfat thickness of carcass reducing to 0% the rejections at slaughterhouse for lack of fatness. & 2016 Elsevier B.V. All rights reserved.
Keywords: Pig immunocastration Sex Growth performances Carcass fatness Meat
1. Introduction In Spain, the dry-cured ham industry requires a minimum of carcass weight (86 kg) and of fat thickness over the Gluteus medius muscle (m. GM; 20 mm) and a maximum of C18:2n-6 proportion in subcutaneous fat (12% and 15% in fresh and cured pieces, respectively) to guarantee the adequate processing and end quality (Daza et al., 2012). Taking into account these considerations, some studies have concluded that barrows would be preferred to gilts for that aim (Peinado et al., 2008, 2011). In fact, Latorre et al. (2008, 2009) detected that around 30% of carcasses were rejected n
Corresponding author. E-mail address: [email protected] (M.A. Latorre).
http://dx.doi.org/10.1016/j.livsci.2016.05.014 1871-1413/& 2016 Elsevier B.V. All rights reserved.
at slaughterhouse, mainly due to the lack of fatness, being all gilts. Moreover, it has been demonstrated that pork from barrows has higher intramuscular fat content than that from gilts (RodríguezSánchez et al., 2011, 2014) which is desirable because of its beneficial effects on eating quality (Fernández et al., 1999). For all of that, strategies to increase backfat thickness and intramuscular fat proportion in gilts are being studied such as the surgical castration. This method of castration has been practiced in males for centuries to prevent the boar taint and aggressive behavior with higher body fatness as a collateral effect (Barton Gade, 1987; Meier-Dinkel et al., 2015). In females, a similar impact in fatness has been observed (Peinado et al., 2011, 2012). However, currently in Spain, surgical castration is only permitted in males, with a plan to voluntarily end it in the EU in 2018 by animal
A. Daza et al. / Livestock Science 190 (2016) 20–26
welfare reasons (PIGCAS, 2009), and exceptionally in females, when are reared outdoor to avoid pregnancies by wild boars, using prolonged analgesia and anesthesia (Boletín Oficial Estado, 2009). In this context, the immunocastration is being evaluated as possible substitute to physical castration. Its effects in males have been widely studied (Pauly et al., 2009; Fábrega et al., 2010; Gispert et al., 2010; Morales et al., 2011; Font i Furnols et al., 2012, 2016), with some controversial results, but the information about its use in females is really limited and focused in autochthonous breeds. So Gómez-Fernández et al. (2013) concluded that the immunocastration could be an interesting economical alternative, in Iberian gilts, to the surgical castration because improved growth performances and had a clear positive influence on pig welfare. Daza et al. (2014) carried out a small trial using commercial gilts with no conclusive results. Although it reported that immunocastration increased fatness, the slaughter was carried out with different BW (130 and 124 kg for immunocastrated and intact females, respectively) which could have affected those variables. The objective of the present experiment was to evaluate the effects of immunocastration of males and females in productive performances and carcass and meat quality when are intended for elaboration of dry-cured ham.
2. Material and methods 2.1. Animal husbandry and feeding All the experimental procedures used in the trial were in compliance with the Spanish guidelines for the care and use of animals in research (Boletín Oficial Estado, 2007). A total of 48 Duroc (Landrace Large White) pigs, 24 males and 24 females, with 8573 d of age (46.3 and 42.9 kg of body weight (BW), respectively) were used. All of them came from the same farm where they had previously had the same feeding and management. On arrival at the experimental facilities (El Chantre, Teruel, Spain), pigs were individually weighed, housed in a controlled environment barn and randomly allotted to 16 pens (2.30 m 2.6 m and 30% slotted floor) of three animals each, according to the sex and BW. The study was conducted as a completely randomized design that included four experimental treatments according to the pig sex or method of castration: surgical castrated males (SCM), immunocastrated males (ICM), entire females (EF) and immunocastrated females (ICF). The surgical castration had been previously done in the origin farm in 12 males with 5 73 d of age. The immunocastration consisted in two vaccines against GnRH with Improvacs (Zoetis, Madrid, Spain) and was carried out in 12 males and 12 gilts following the recommendations of the company; at days 0 and 28 of the trial (with 45.4 and 70.6 kg BW as average, respectively). The feeding program was common for all pigs consisting in a commercial diet that included (per kg of feed): 537 g barley, 200 g wheat, 130 g rapeseed meal, 40 g sunflower meal, 40 g wheat flour, 12.5 g blended fat, 10.0 g molasses sugarcane, 13.3% calcium carbonate, 2.7 g dicalcium phosphate, 4.5 g sodium chloride, 0.6 g L-lysine 50%, 0.6 g DL-methionine 99%, 6.6 g L-threonine and 2.0 g vitamin and mineral premix. The estimated energy content (FEDNA, 2010) and the analysed nutritional composition of diet is shown in Table 1. Pigs had ad libitum access to pelleted diet, in a single space feeder, and water throughout the trial and were slaughtered on the same day with 16773 d of age (126 kg BW as average). 2.2. Growth performances Individual BW was recorded at day 0 (beginning of the trial and 1st Improvac vaccine), day 28 (2nd Improvac vaccine), day 63 and
21
Table 1 Nutrient composition of the diet used in the trial for pigs from 85 to 167 d of age. g/kg, as-fed basis Calculated analysisa Digestible energy (MJ/kg) 13.74 Determined analysis Dry matter Crude protein (N 6.25) Crude fiber Crude fat
883.3 139.1 51.3 32.1
Fatty acids C14:0 C16:0 C18:0 C18:1n-9 C18:2n-6 C18:3n-3
0.29 4.14 1.31 4.98 16.34 2.99
a
According to FEDNA (2010).
day 82 (end of the trial) to calculate average daily gain (ADG). The average daily feed intake (ADFI) was calculated per pen, for the periods 0–28, 28–63, 63–82 and 0–82 d of the trial, taking into account the feed given and the orts. After, the data of ADG and ADFI per pen were used to calculate the feed conversion ratio (FCR) for the same periods. In addition, data of fat thickness (in mm) were taken at days 28, 63 and 82 of the trial using ultrasound RTU equipment (Kretz Technick Inc, 600V-V2.232, Sonovet, Austria). After a previous calibration according to manufacturer recommendations, measures were recorded by the same operator, on the right side of all animals, at last rib level, over the skin without clipping the hair. 2.3. Slaughter, carcass measures and sampling The day before slaughter, feed was withdrawn 8 h and pigs were transported to a commercial abattoir (35 min transport time) using a single-decked trailer, equipped with upper hydraulic floor, with capacity for 120 pigs distributed into 8 separate compartments. The truck was driven with the 80 experimental pigs being distributed into 4 compartments only (loading density of 0.56 m2/pig). Pigs belonging to the same treatment were allotted to the same box. At the slaughterhouse, animals were kept in lairage for 10 h, with full access to water but not to feed, and after they were electrically stunned (225–380 V/0.5 A for 5–6 s), exsanguinated, scalded, skinned, eviscerated, and split down the midline according to standard commercial procedures. The following measures were individually taken from all carcasses (12 per treatment). Hot carcass weight was recorded to calculate dressing percentage. At 45 min postmortem, carcass length (from the posterior edge of the Symphysis pubis to the anterior edge of the first rib), ham length (from the anterior edge of the Symphysis pubis to the hock joint) and ham perimeter (at its widest side) were measured on the left carcass side by a tape of centimeter precision. Carcass compactness was then calculated as carcass weight/carcass length. In addition, on the same carcass side, backfat thickness was measured at the level of the 10th rib and over the m. GM (skin included) using a rule of millimeter precision. The proportion of rejected carcasses was calculated using the fat thickness at m. GM (o20 mm) as the criterion. The percentage of lean in carcass was estimated according to ZP method (Diario Oficial Unión Europea, 2012) by the following equation: lean proportion (%)¼58.89–0.821F-ZPþ 0.157 M-ZP where F-ZP was the fat depth at m. GM and M-ZP was the shortest connection between the front (cranial) end of the m. GM and the upper (dorsal) edge of the vertebral canal measured also by rule.
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A. Daza et al. / Livestock Science 190 (2016) 20–26
After refrigeration at 2 °C (1 m/s air speed; 90% relative humidity) for 6 h, carcasses were processed according to commercial standards. The ham and shoulder from the left side of each carcass were trimmed, to fit commercial requirements, and individually weighed to calculate their yield. After processing, from all carcasses, a section of 500 720 g of Longissimus thoracis muscle was excised at the level of the last rib from the left loin. A subcutaneous fat sample (607 4 g), including fat layers, skin and lean was also taken from each carcass at the tail insertion in the coxal region. From each meat sample, one 2-cm-thick slice was taken for measuring color and the rest, as well as the fat samples, were vacuum-packaged in individual bags and stored at 20 °C until subsequent analyses. 2.4. Laboratorial analyses The fresh slices were displayed on polystyrene trays, overwrapped with oxygen–permeable polyvinyl chloride wrap and stored at 4 °C during 3 d. Color stability was assessed by measurements days 1, 2 and 3 of display in air at 4 °C, after blooming for 1 h, using a chromameter (Model CM 2002; Minolta Camera, Osaka, Japan), with illuminant D65 and 10° standard observer. The average of three random readings was used to measure: lightness (L*), redness (a*) and yellowness (b*) (Commission internationale de l’Eclairage, 1976). Additionally, chroma (C*) was calculated as C* ¼√(a*2þb*2) which is related to the quantity of pigments (Wyszecki and Stiles, 1982). Also, the three myoglobin species were calculated as ratios of measurements at then given wavelengths; deoxymyoglobin (dMb; 473 nm/525 nm), oxymyoglobin (oMb; 610 nm/525 nm) and metmyoglobin (metMb; 572 nm/ 525 nm). Chemical analysis of feed for dry matter (930.15), crude protein (984.13) and crude fiber (978.10) was carried out according to AOAC (2005) procedures. The fatty acids of the diet were extracted and quantified by the one-step procedure described by Sukhija et al. (1988) in lyophilized samples. Pentadecenoic acid (C15:1) (Sigma, Alcobendas, Madrid, Spain) was used as internal standard. Previously, methylated fatty acid samples were identified according to Rey et al. (1997) using a gas chromatograph (Model HP6890; Hewlett Packard Co., Avondale, PA, USA) and a 30 m 0.32 mm 0.25 mm cross-linked polyethylene glycol capillary column (Hewlett Packard Innowax, Avondale, PA, USA). A temperature program of 170–245 °C was used. The injector and detector were maintained at 250 °C. The carrier gas (helium) flow rate was 3 mL/min. Lipids from subcutaneous fat (outer and inner layers separately) were extracted by the procedure proposed by Bligh et al. (1959) while lipids from intramuscular fat were obtained according to the method developed by Marmer et al. (1981). Fat extracts were methylated in the presence of sulphuric acid and analysed as described above. The proportion of total saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids were calculated from individual fatty acid percentages.
was used to evaluate the normal distribution of data using the transformation arc sin (x/100)0.5 for those whose distribution was not normal (ham and shoulder yields, as well as percentage of rejected carcasses because of low fatness). A P-value of r 0.05 was considered as a significant difference between treatments and a Pvalue between 0.05 and 0.10 as a trend.
3. Results 3.1. Growth performances The effect of immnocastration on males and females on productive performances is shown in Table 2. From days 0 (1st vaccination) to 28 of the trial, EF grew faster than ICF with the groups of males (SCM and ICM) being intermediate (P ¼0.005). In addition, EF tended (P ¼0.09) to eat more and ICF tended (P¼ 0.09) to be less efficient converting feed into gain than the other treatments. From days 28 (2nd vaccination) to 63 and also from days 63–82 of the study (slaughter), no significant effect was detected for the growth performance traits evaluated. During the overall period (from days 0 to 82), SCM had higher FCR than the rest of the treatments (P ¼0.049). Therefore, at slaughter, ICM were heavier than SCM and ICF with EF being intermediate (P ¼0.05). Also, ICF
Table 2 Growth performances and fat depth in vivo measurements of surgical castrated males (SCM), immunocastrated males (ICM), entire females (EF) and immunocastrated females (ICF) intended for dry-cured ham production. Variablea
ICM
EF
45.0
47.6
42.7
70.2xy
69.1yz
72.1x
104.9 124.3y
106.7 131.0x
109.3 126.7xy
From 0 to 28 d of trial ADG (kg/d) ADFI (kg/d) FCR
0.912xy 2.27 2.48
0.874yz 2.20 2.47
0.981x 2.33 2.42
0.806z 0.028 2.20 1.072 2.78 0.101
0.005 0.09 0.09
From 28 to 63 d of trial ADG (kg/d) ADFI (kg/d) FCR
0.990 3.00 3.06
1.050 3.00 2.86
1.070 2.94 2.74
1.030 3.65 2.85
0.033 0.363 0.102
0.34 0.49 0.22
From 63 to 82 d of trial ADG (kg/d) ADFI (kg/d) FCR
1.120 4.03 3.64
1.230 4.03 3.34
1.150 3.93 3.43
1.440 4.02 2.90
0.114 0.051 0.231
0.20 0.47 0.19
From 0 to 82 d of trial ADG (kg/d) ADFI (kg/d) FCR
0.993 2.97 2.99x
1.040 2.96 2.75y
1.050 2.92 2.84y
1.030 2.90 2.85y
0.203 0.035 0.051
0.18 0.44 0.049
10.0 15.1 22.3xy
10.6 15.5 22.4xy
10.0 14.7 20.7y
0.63 0.46 0.67
0.60 0.44 0.05
BW, kg At day 0 (vaccination 1) At day 28 (vaccination 2) At day 63 At day 82 (slaughter)
2.5. Statistical analyses Data were analysed using the statistical package SPSS-16. The model included the pig sex or method of castration (SCM, ICM, EF and ICF) as main effect and the initial BW as covariate for productive performances when was significant. Duncan's test was used to assess differences between treatment means. In order to estimate the relationships between oMb/metMb ratio and ageing (days), regression analysis was carried out. Each treatment was replicated 4 times for growth performance traits (experimental unit ¼pen with 3 pigs each) and 12 times for carcass, meat and fat variables (experimental unit ¼animal). Shaphiro et al. (1965) test
SCM
Fat depth (mm) At day 28 At day 63 At day 82 (slaughter) a
ICF
SEM (n ¼4)
P-value
43.2
1.25
0.06
67.2z
0.80
0.005
102.9 125.7y
1.82 1.60
0.10 0.05
9.3 14.5 23.1x
BW: body weight; ADG: average daily gain; ADFI: average daily feed intake; FCR: feed conversion ratio. x,y,z Within a row, means without a common superscript letter differ (Po 0.05).
A. Daza et al. / Livestock Science 190 (2016) 20–26
effects (Table 4). Pork from ICF was redder than that from ICM with SCM and EF in intermediate positions (Po 0.001). Also, meat from SCM showed a more intense color (higher C*) (P ¼0.03) and tended to have lower contents in oMB (P¼ 0.061) and in metMb (P ¼0.082) than that from EF with immunocastrated pigs (ICM and ICF) being intermediate. Loin from ICF showed lower oMb/metMb ratio than the other treatments (P ¼0.001). The intramuscular fat content was not affected by the experimental treatment. With respect to ageing, the redness (P ¼0.01) and chroma (P o0.001) were higher at days 1 and 2 than at day 3. Also, the yellowness decreased in the order day 1 42 43 (Po 0.001), whereas the oMB level (P o0.04) and oMb/metMb ratio (P ¼0.001) increased in the opposite way (day 3 42 4 1).
Table 3 Carcass characteristics of surgical castrated males (SCM), immunocastrated males (ICM), entire females (EF) and immunocastrated females (ICF) intended for drycured ham production.
Carcass weight (kg) Carcass yield (%) Carcass length (cm) Ham length (cm) Ham perimeter (cm) Carcass compactnessa Backfat thickness (mm) At 10th rib At Gluteus medius muscle Carcass rejected (%)b Lean yield (%)c
SCM
ICM
EF
ICF
SEM (n ¼ 12)
P-value
95.8 77.1 88.4 41.0 74.8 1.08
100.6 76.9 90.8 41.0 73.4 1.11
98.8 77.0 88.6 40.5 76.0 1.12
97.2 75.9 88.2 39.9 75.7 1.10
2.35 0.56 0.84 0.54 0.77 0.020
0.52 0.42 0.12 0.48 0.92 0.70
27.7xy 21.3xy
28.0xy 22.4xy
25.2y 28.3x 1.03 20.2y 23.6x 0.91
0.05 0.043
0y 52.3xy
0y 51.1xy
25x 0y 6.68 53.2x 50.0y 0.90
0.025 0.048
14.6 8.06 22.6
14.0 8.06 22.0
14.5 8.01 22.5
0.065 0.17 0.12
23
3.4. Fatty acid profile of subcutaneous and intramuscular fat
Carcass weight (kg)/carcass length (cm). Carcasses which did not fulfill the minimum required backfat thickness at Gluteus medius muscle (20 mm). c Calculated according to ZP method (Diario Oficial Unión Europea, 2012). d Ham þ shoulder from half a carcass. x,y Within a row, means without a common superscript letter differ (Po 0.05).
The inmunocastration of males or females had limited influence on major fatty acids of outer and inner subcutaneous backfat layers (Table 5). Only, the C18:1n-9 proportion of outer backfat was affected being lower in ICM than in the groups of females (EF and ICF) with SCM being intermediate (P o0.05). Similarly, in the fatty acid profile of intramuscular fat, no differences were observed. In addition, the total SFA, MUFA and PUFA, the sum of n-6 and n-3, and also the C16:1n-6/C16:0, C18:1n-9/C18:0, MUFA/ SFA, PUFA/SFA and n-6/n-3 ratios in both types of fat (subcutaneous and intramuscular) were not affected by experimental treatments (data not shown).
had wider backfat thickness, measured in vivo, than EF with both groups of males in an intermediate position (P ¼0.05).
4. Discussion
Yield main cuts (% carcass) Ham Shoulder Totald
14.3 7.84 22.2
0.16 0.076 0.19
a
b
3.2. Carcass quality
It has to be noted that this was a preliminary study and the number of replicates per treatment was limited.
The inmunocastration had no effect on carcass yield or ham size (Table 3). However, the ICF was fatter, measured at 10th rib (P¼0.05) and at m. GM (P¼ 0.043), than EF with males (SCM and ICM) being intermediate. As a consequence, EF had the leanest carcasses (P¼0.048) and 25% of them were rejected for lack of fatness (P¼0.02). Also, SCM and EF tended (P¼ 0.065) to show higher ham yield than immunocastrated animals (males and females).
4.1. Growth performances The information about immunocastration in gilts is very scarce which complicates in part the present discussion. In the current trial, from the 1st to the 2nd injection, ICF grew slower and tended to eat less feed and to be less efficient converting feed into gain than EF. However, no difference was detected between SCM and ICM. It suggests that the effect of the 1st Improvac vaccination had different effects in both sexes with no influence in males but impairing the growth productive traits in gilts. In males, Morales et al. (2011, 2013) found that ICM had lower ADFI and ADG
3.3. Meat characteristics No significant interaction was detected between sex and ageing for meat characteristics; therefore, results are shown by main
Table 4 Meat characteristics of surgical castrated males (SCM), immunocastrated males (ICM), entire females (EF) and immunocastrated females (ICF) intended for dry-cured ham production. Sex
Color traits Lightness, L* Redness, a* Yellowness, b* Chroma, C* Myoglobin speciesa dMb oMb metMb oMb/metMb Intramuscular fat (%) a
Ageing (d)
P-value
SCM
ICM
EF
ICF
SEM (n ¼12)
1
2
3
SEM (n¼ 48)
Sex
Ageing
Sex ageing
55.0 3.14y 13.9 14.4x
54.6 2.25z 13.2 13.4yz
52.8 2.63yz 13.0 13.3z
53.9 4.21x 13.5 14.2xy
0.82 0.23 0.30 0.31
54.9 3.23x 14.2x 14.7x
54.3 3.38x 13.4y 13.9x
53.1 2.57y 12.6z 12.9y
0.71 0.20 0.26 0.27
0.21 o 0.001 0.11 0.03
0.22 0.01 o 0.001 o 0.001
0.69 0.74 0.64 0.63
1.06 3.71 7.71 0.50x 5.24
1.05 4.53 8.88 0.51x 4.22
1.06 5.71 10.8 0.52x 4.33
1.06 4.66 10.6 0.45y 4.59
0.008 0.53 0.99 0.012 0.382
1.09x 3.99y 9.19 0.43z –
1.04z 4.38xy 9.13 0.48y –
1.06y 5.59x 10.2 0.56x –
0.007 0.46 0.86 0.010 –
0.57 0.06 0.08 0.001 0.25
o 0.001 o 0.04 0.63 0.001 –
0.83 0.78 0.65 0.34 –
dMb: deoxymyoglobin (at 473 nm/525 nm); oMb: oxymyoglobin (at 610 nm/525 nm); metMb: metmyoglobin (at 572 nm/525 nm). Within a row, means without a common superscript letter differ (P o 0.05).
x,y,z
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A. Daza et al. / Livestock Science 190 (2016) 20–26
Table 5 Major fatty acids of subcutaneous and intramuscular fat from surgical castrated males (SCM), immunocastrated males (ICM), entire females (EF) and immunocastrated females (ICF) intended for dry-cured ham production. % of total fatty acids SCM
ICM
EF
ICF
SEM (n¼ 12) P-value
Subcutaneous fat
Outer layer C16:0 C18:0 C18:1n-9 C18:2n-6
23.38 14.88 39.35xy 11.82
23.48 23.28 23.29 15.22 15.00 15.43 38.63y 39.44x 39.81x 11.97 11.59 11.36
0.201 0.253 0.282 0.302
0.88 0.42 o 0.05 0.54
Inner layer C16:0 C18:0 C18:1n-9 C18:2n-6
24.82 17.40 37.62 10.32
24.52 17.15 38.02 10.51
24.49 17.02 38.38 10.45
24.31 17.28 38.62 10.10
0.192 0.271 0.313 0.284
0.28 0.76 0.15 0.74
Intramuscular fat C16:0 C18:0 C18:1n-9 C18:2n-6
24.62 14.72 41.63 7.26
24.38 14.97 41.02 7.61
24.62 14.20 42.15 7.17
24.46 14.53 42.09 7.28
0.224 0.245 0.423 0.262
0.82 0.16 0.22 0.65
x,y
Within a row, means without a common superscript letter differ (Po 0.05).
compared to SCM with similar FCR. Authors justified it by the stress of the injection (Fábrega et al., 2010) and an increase of the body temperature (Pauly et al., 2009). In the case of females, in a preliminary study, Daza et al. (2014) did not find significant differences between EF and ICF. From the 2nd Improvac vaccination to the slaughter, in the current experiment, ICM had 8% better FCR than SCM but it was not statistically significant which is in agreement with the results of Metz et al. (2002). However, taking into account the most of literature papers, better growth performances were expected in ICM than in SCM and we do not have an explanation for it. In fact, in a meta-analysis that included 41 experiments, Batorek et al. (2012) found that ICM displayed higher ADFI and ADG and better FCR than SCM attributing it to a reduction of steroidogenic capacity (Dunshea, 2010) and to a quick decrease of testosterone concentration after the injection (Zamaratskaia et al., 2008). With respect to females, the FCR was similar (2.98 vs 2.86 for EF and ICF, respectively) which agrees with the work of Daza et al. (2014) evaluating gilts of the same crossbred and similar slaughter BW. For the overall period, the SCM had higher FCR than ICM, EF and ICF (by 8.7%, 5.3% and 4.9%, respectively). Morales et al. (2011) also detected better FCR in ICM than in SCM from 31 to 123 kg BW. After, Morales et al. (2013) compared SCM, ICM and EF from 42 to 125 kg BW observing better feed efficiency in ICM than in the other treatments. The groups of females (EF and ICF) had similar growth performance results, in agreement with the preliminary study of Daza et al. (2014). The discrepancies among experiments might be related to differences in the pig genetic crossbred as well as to aspects relative to the Improvac use (i.e. age at vaccinations or number of injections). 4.2. Carcass quality Results of backfat depth in carcass measured by rule confirmed data recorded by ultrasounds in in vivo animals just before slaughter. It is widely accepted that surgical castration of males increased carcass fatness compared to boars (Nold et al., 1997; Weatherup et al., 1998). Suster et al. (2006) explained the increased lipolysis and the decreased muscle accretion in SCM by a reduced production of growth hormone and IGF-1. However, comparing SCM and ICM, literature is more controversial. Dunshea
et al. (2001) found higher backfat depth in SCM and similar results were detected by Morales et al. (2011, 2013) who also measured lean percentage being lower in SCM. However, in the current trial, no effect of immunocastration was detected in this sense. Zeng et al. (2002) evaluated SCM and IMC vaccinated at 70 and 119 d of age and slaughtered at 161 d of age and 110 kg of BW with similar finds. The available data suggest that carcass quality of ICM is influenced by two main factors: the growth potential of the boars before the second vaccination and the time interval elapsed between the second vaccination and slaughter (Dunshea et al., 2001; Metz et al., 2002). In the current study, irrespectively of method of castration, all males produced fattier carcasses than the minimum required for dry-cured ham elaboration. In the case of SCM, it was expected because Latorre et al. (2008, 2009) reported similar results but, in the case of ICM, which were more unpredictable, they can be considered very positive. The immunocastration was very effective increasing backfat thickness in females, and then the lean yield was higher in EF than in ICF, which agrees with results of Oliver et al. (2003) and Daza et al. (2014). Other authors (Serrano et al., 2008; Peinado et al., 2011) have also found that the gilt surgical castration increased carcass fatness in comparison to EF. As a consequence of the results of fat depth at m. GM, the proportion of carcasses rejected at slaughterhouse from ICF was 0% whereas from EF was 25% which is a success of the immunocastration. The percentage of rejects in EF confirms the results of Latorre et al. (2008, 2009) who quantified it in almost 30%. Other positive effect of immunocastration in females was that ham or shoulder yield was not penalized, in agreement with data of Gómez-Fernández et al. (2013). Those authors observed, in Iberian gilts slaughtered at 160 kg BW, similar weight of these major pieces in EF and ICF being, in both cases, higher than in surgical castrated females which would confirm the higher fatness of physically castrated females. 4.3. Meat characteristics Meat color is a sensorial trait that has an important influence on consumers to choose pork products. Several studies did not find any significant effect on pork color of the surgical castration in males (Barton-Gade, 1987; Weatherup et al., 1998) and in females (Serrano et al., 2008; Peinado et al., 2008, 2011) in comparison to entire animals. In the present study, the loin from SCM had higher a* and C* values than that from ICM indicating a more intense color in pork from the first ones. Lowe et al. (2014), fourteen days after slaughter, also observed that SCM had redder and more yellow pork than ICM. In females, the immunocastration provided higher a* and C* values in meat whereas Daza et al. (2014) did not detect any effect. Comparing immunocastrated animals, meat from ICF was redder than that from ICM. Several factors can have influence on color pork such as the management of animals during transportation and at abattoir, the slaughter method and the conditions of data collection (Mancini and Hunt, 2005). There are few studies about the effect of ageing on color stability of pork. The three myoglobin species found in fresh meat (dMb, oMb and metMb, related to purple, bright red or brown color, respectively) have different reflectance spectra and hence different colors, and tristimulus color parameters (L*, a* and b* values) are shown to vary according to the myoglobin species. The evolution of redness, yellowness, intensity of color (C*) and oMb showed a clear discoloration as time goes. In fact, a linear regression equation was obtained between oMb/metMb ratio and time: oMb/metMb ¼0.367þ0.0633 ageing (in days) (R2 ¼0.47; Po 0.001) indicating a higher ratio from days 1 to 3. Our results confirm those of Rosenvold et al. (2003) and also those of Lindahl et al. (2006) who evaluated color variables through 9 d of aerobic storage.
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There was no significant difference among treatments in intramuscular fat content although it was 24% higher in SCM than in ICM and 6% higher in ICF than in EF. The lack of differences between SCM and ICM is consistent with results of Gispert et al. (2010), Font i Furnols et al. (2012) and Morales et al. (2013). Daza et al. (2014) neither found differences between ICF and EF in this variable. 4.4. Fatty acid profile of subcutaneous and intramuscular fat Limited differences were observed among treatments in the fatty acid profile of fat. Only C18:1n-9 proportion of the outer layer of subcutaneous fat was higher in females (EF and ICF) than in ICM being SCM intermediate. In general, the practice of surgical castration increases body fatness and then SFA also increases as much in males (Mackay et al., 2013) as in females (Serrano et al., 2008; Peinado et al., 2011). The main fatty acids produced from de novo synthesis are the palmitic and stearic; therefore, as pigs continue depositing fatty acids and adipocytes fill with triglycerides from de novo synthesis, the proportion of SFA in adipose tissue is increased (Wood et al., 2008). About immunocastration of males, our lack of differences agree with the study of Font i Furnols et al. (2012) but Tavárez et al. (2014) found higher PUFA in belly adipose tissue of ICM than in that of SCM. Also, Mackay et al. (2013) detected higher ∑n-6 in ICM explaining it by changes in lipogenic enzyme protein expression. In females, some authors observed higher PUFA in ICF than in EF (Gamero-Negrón et al., 2015) whereas others (Daza et al., 2014) reported in ICF higher C16:0, C18:0 and SFA and lower C18:1n-9 and MUFA and C18:2n-6 and PUFA proportions in subcutaneous backfat and intramuscular fat of loin. The reasons for the lack of effects in the current trial could be the small differences in backfat depth (2–3 mm), being lower than in other trials and even no influence was observed in the intramuscular fat content. In fact, Wood et al. (2008) reported that at least 4 mm of difference are required to detect changes in the fatty acid profile. Moreover, in the current work, the time elapsed from the second vaccination to slaughter (54 d) could not be enough to modify fat composition according to the work of Asmus et al. (2014).
5. Conclusions Under our experimental conditions, it can be concluded that the immunocastration in males improved feed conversion ratio and did not decrease carcass fatness, in comparison to those physically castrated, which is positive in pigs intended for drycured ham elaboration. In females, the immunization against GnRH did not penalize growth performances and increased fat depth at m. GM which carried out no carcass rejection at slaughterhouse. Finally, the use of Improvacs had limited effect on pork quality and fatty acid profile but it seems increasing the homogeneity between sexes (males and females) in terms of productive performance and quality.
Acknowledgements This research was supported by Project PET-2007-08C11-05 (INIA). Thanks to E. Feliz de Vargas and I. Garitano (El Chantre, Teruel, Spain) for the control of animals and to L. Ariño (Jamones y Embutidos Alto Mijares S. L., Teruel, Spain) for the help during the slaughter and sampling. References AOAC, 2005. Horwitz, W., Latimer, G.W. (Eds.), Official methods of analysis, 18th ed. Association of Official Analytical Chemists, Gaithersburg, MA.
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