DOI: https://doi.org/10.52973/rcfcv-e32154
Received: 13/05/2022 Accepted: 13/06/2022 Published: 26/08/2022
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Revista Cientíca, FCV-LUZ / Vol. XXXII, rcfcv-e32154, 1 - 9
ABSTRACT
Pampa Rocha pig (PRp) is a local breed present and produced in
Uruguay. Twenty-three pigs were used housed indoor (I) and outdoor
with pasture (O), live weight 94.5 and 91.5 kilograms (kg), respectively.
Animals were fed with concentrate in both systems, but pasture
access was granted to the animals in the O. After slaughtering,
the Longissimus dorsi (LD), Psoas major (PM), Gluteus medius (GM),
Semitendinosus (ST), Biceps femoral (BF), and Quadriceps femoris
(QF) were sampled to be analyzed. In O, the growth of pigs was lower,
and improved the concentrate intake:live weight gain. The content
of heme iron and the ratio Fe Heme/Fe Total were higher in outdoor.
The LD muscle showed lower total and heme iron content. For ham,
QF showed the highest values of heme iron. No differences were
observed between systems or muscles in the content of Ca, Mg, and
K. The Na content was similar in both systems, and higher in PM. No
differences were observed between production systems for trace
elements content. According to the results obtained, it is possible to
produce PRp meat with interesting mineral content, in two alternative
systems to the classic connement. This breed produces healthier
meat in O. It could be interesting to exploit some differences founded
between LD and PM muscles, which are normally consumed as fresh
meat, and are adapted to the different demands of human nutrition.
Rearing in O that include pastures is a good way to promote and add
nutritional value to this local breed.
Key words: Pampa Rocha pig; macro mineral; trace element; heme
iron; outdoor production system
RESUMEN
El cerdo Pampa Rocha (PRp) es una raza criolla uruguaya. Se utilizaron
23 cerdos alojados en dos sistemas: cama profunda (I), o al aire libre
con pasturas (O), faenados a los 94,5 y 91,5 kg, respectivamente. En
ambos sistemas se alimentaron con concentrado comercial, teniendo
acceso a libre pastoreo en el sistema O. Inmediatamente luego de la
faena, se tomaron muestras de los músculos para análisis: Longissimus
dorsi (LD), Psoas major (PM), Gluteus medius (GM), Semitendinosus (ST),
Biceps femoral (BF) y Quadriceps femoris (QF). Los cerdos criados en O
mostraron un crecimiento más lento, pero mejoraron la conversión
de concentrado. El contenido de hierro heme y la relación Fe Heme/
Fe total fue mayor en O. En el LD se observó menor contenido de
hierro heme y total, pero en músculos del jamón, el QF mostró los
valores más altos de hierro heme. No se observaron diferencias entre
sistemas o músculos para los contenidos de Ca, Mg y K. El contenido
de Na fue similar entre sistemas y mayor en PM. No se observaron
diferencias entre sistemas para el contenido de elementos traza.
Según los resultados obtenidos es posible producir carne de cerdo
PRp con contenidos interesantes de minerales, en dos sistemas
alternativos al connamiento clásico, siendo más saludable desde el
punto de vista nutricional aquella producida en O. Sería interesante
aprovechar algunas diferencias encontradas entre los músculos
LD y PM, que son consumidos normalmente como carne fresca, y
que por sus valores se adaptan a las necesidades de la nutrición
humana. La cría en O que incluya pasturas implica una alternativa
de producción que adiciona valor nutricional y a su vez valoriza esta
raza porcina local.
Palabras clave: Cerdo Pampa Rocha; macro minerales; elementos
traza; hierro heme; sistema de producción al aire
libre
Trace elements, macro minerals and iron forms content, in meat of Pampa
Rocha pig reared indoor and outdoor with pasture
Contenido de elementos traza, macro minerales y formas de hierro en carne de cerdo Pampa Rocha
criado en connamiento o al aire libre con pasturas
Cecilia Carballo
1
* , Nandy Espino
1,2
, Ana Vodanovich
1
, Marcelo Ferrando
3
, Ali Saadoun
1,2
and María Cristina Cabrera
1,2
1
Universidad de la República, Facultad de Agronomía, Departamento de Producción Animal y Pasturas, Laboratorio de Calidad de Alimentos & Productos.
Montevideo, Uruguay.
2
Universidad de la República, Facultad de Ciencias, Fisiología & Nutrición, Instituto de Biología. Montevideo, Uruguay.
3
Universidad de la República, Facultad de Agronomía, Departamento de Suelos y Aguas. Montevideo, Uruguay.
*email: ccarballo@fagro.edu.uy
Minerals in meat of local breed pig / Carballo et al. ________________________________________________________________________________
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INTRODUCTION
Pampa Rocha pig (PRp) is a local genetic animal resource reared in
Uruguay, mainly in Rocha, East region of the Country [9, 35], whose
population is in danger-maintained condition [14], and its revaluation
being important to recover it. In that region, family-scale producers
work hardly to conserve that local pig (Sus scrofa domesticus) and
look how it can be valued though its products, such as meat, in a
rst step for the local market and afterward in the international one.
Much remains to be done, and the producers need scientific
information regarding the meat quality parameters of the PRp to help
them to do their promotion campaigns. Two advantageous points could
help this pig to grow as a meat product for local and regional consumers.
The rst one is that the pig meat is growing within the international
meat market in comparison to others usual meat [29]. The second
one is that consumers today ask for differential and local products [6].
By other side, pork is a traditional and valuable source of protein and
micronutrients in many low-income countries, contributing with the
physical and cognitive development of children and adolescents. In this
sense, in Latin America, pork consumption has risen rapidly in recent
years, particularly in Argentina, Brazil, México, and Uruguay, with this
demand driven by higher domestic production, quality improvements,
and favourable relative prices [29, 30]. Additionally, fertile lands with
abundant pasture represent an opportunity to rear pigs with improved
attributes that might inuence consumer perception.
Globally, consumer demands are changing, and recent outbreaks of
animal diseases have raised health and safety food concerns [13]. As
previous studies have demonstrated that nutrients as mineral content
can vary among animal species, diets, genetic types, muscles, ages,
and processes [2, 4, 10, 31, 34] and some mineral, particularly Fe
content can to best in outdoor systems and in the local breeds [27,
40]. The accurate determination of nutrient content in a new animal
protein food is necessary to accomplish the nutritional value of the
different cuts of meat in relation to their economic value [4, 37].
People increasingly prefer ecologically friendly or organic meat
products that are antibiotic-free and produced in line with ethical and
animal welfare standards [15]. Outdoor (O) production represents an
opportunity to meet these new demands, and future systems should
include creole local breeds and pastures to add value to meat products.
On the other hand, the deep bed system is present in Uruguay and in
the region as an alternative system to classic conned one. As main
characteristics, the best animal welfare is mentioned because de litter
(dry vegetable matter) enriches the environment, water is not used for
cleaning and there is no management of excreta. Low-cost facilities
can be used, making this system viable on family farms [12].
If PRp meat is valued and become a commercial product, so this
genetic resource animal will be protected and preserved in its original
ambient for the next generation of producers. This economic schema
has been useful to protect and preserve other productive species in
other countries. Probably the most illustrative example would be the
Iberian pig, today produced in Spain and famous for its products as
delicatessen, known worldwide [31]. PRp is far to be at the same level
and status that the Iberian pig, but availability of nutritional information
of this kind of animal could help it to grow as a differential product.
Thus, the objective of this investigation was to evaluate the nutritional
value of fresh meat obtained from PRp produced in Uruguay in two
alternative production systems to classic conned, outdoor with
pastures and deep bed, both possible to be adopted by family
producers. The present investigation has been focused on trace and
macro minerals, as well as on heme and non-heme iron, zinc, copper,
manganese, calcium, magnesium, sodium, and potassium contents
in the Longissimus dorsi, Psoas major, and ham muscles, i.e., Gluteus
medius, Semitendinosus, Biceps femoral, and Quadriceps femoris.
MATERIALS AND METHODS
Animals and feeding
The whole experiment was conducted with the approval of the
animal ethical committee of the Faculty of Agronomy (Udelar-Uruguay,
protocol N° 317, le N° 021130-001003-16). Twelve males (castrated)
and eleven females PRp born in an O system, were weaned at 45 days
of age (DA), live weight (LW) 14.5 ± 3.5 kg, and housed in group, both
sex mixed, in a shed. The sides of the shed were fenced with wire
mesh and the litter was made of wheat straw.
The animals remained in there until they reached the LW of
39.6kg±2.8. Then 11 animals (6 males and 5 females) were kept in
the same shed, providing 1.5 square meters (m
2
) of oor per animal
(Indoor, I). The other 12 animals (8 males and 4 females) were housed
grouped in eld facilities, next to the shed, fenced with wire mesh
too (O with pasture). The animals of the O system have always access
to a refuge and cultivated pastures, having an available grazing area
of 300 m
2
per animal.
The criteria for composed the groups in each treatment was the
similar weight when pigs were assigned to each production system, and
presence of male and female pigs in both. Both housing systems had
feeders for concentrate and automatic water sources with permanent
access. The concentrate characteristics are showed in the TABLE I.
In the I system, feed offered was calculated according to LW, at
rate of 100% of maximum voluntary intake (MVI) [28]. In the O system
with access to pasture, diet intake was restricted by 15% of MVI, up to
67.50 ± 12.79 kg of LW; after that, there was a subsequent restriction of
25% until the sacrice. This procedure was applied to favour pasture
TABLE I
Composition and nutrient level of concentrate (air-dry basis)
Ingredient % Nutrient Content %
Rice bran,defatted 20 Dry matter % 90.23
Rice bran, whole 10 DE (Mcal·kg
-1
) 2.79
Sorghum grain, ground 25 Crude Protein 14.49
Corn grain, ground 15 Crude ash 12.11
Wheat grain, ground 15 Ether extract 3.35
Soybean meal, 47 % CP 10 Crude Fiber 8.30
Calcium carbonate 2.5 Calcium 0.63
Salt 0.35 Available phosphorus 0.27
Premix
1
2.15
The premix
1
included: ROVIMIX
®
Pig CT 2 % , vitamin A, D3, E, K3, C,
thiamine, riboavin, pyridoxine, cyanocobalamin, folic acid, pantothenic
acid, copper (as copper sulfate), selenium (as sodium selenite), zinc (as zinc
oxide), iron (as iron sulfate), manganese (as manganese sulfate), iodine,
lysine, threonine, and OXICAP
®
MS (antioxidant) and BioCholine® and
MICOFIX® (mycotoxin binder), and ROVABIOTM (multienzyme complex).
________________________________________________________________________Revista Cientica, FCV-LUZ / Vol. XXXII, rcfcv-e32154, 1 - 9
3 of 9
intake [19]. The cultivated pasture was a mixture, in a dry matter (DM)
basis, of Cichorium intybus (48.6%), Trifolium pratense (34.9%), Lolium
multiorum (12.3%), and undened weed (4.2%). Pasture consumption
was estimated for a period of 7 days (d) prior to slaughter, through the
difference in forage availability at the entrance and exit of the animals
to the grazing strip, applying the double sampling method [25]. At the
end of the experiment, the animals (LW of 94.5±3.6 and 91.5±3.4 kg for
I and O with pasture, respectively), were slaughtered in a commercial
slaughterhouse. Immediately after sacrice, Longissimus dorsi (LD)
between the 10th and 12th ribs, Psoas major (PM), Gluteus medius (GM),
Semitendinosus (ST), Biceps femoral (BF), and Quadriceps femoris
(QF) were removed and transported to the laboratory in refrigerated
isothermal boxes (Rubbermaid Incorporated, Huntersville, USA).
Productive and carcass parameters
Concentrate intake was estimated daily considering the offer and
residual fed. The individual LW (kg) was registered every 14 d. At
slaughtering, carcasses were individually identied and weighted
on an electronic hanging scale (NQF, D5000, Uruguay). The dorsal fat
thickness was measuring in three points of the each LD sample with
caliber milimeters (mm, Kendo, XM2007006, China).
Mineral determinations
For each muscle, a 5 grames (g) sample, free of visible fat and
connective tissue, were used. The samples were dried in a forced-air
oven (105°C, Labotecgroup, BJPX-Juneau, Uruguay), until they reached
a constant weight. Dried samples were then incinerated in a digital
mue furnace (Thermolyne, Cimarec 3, USA), at 580°C for 16 hours (h),
using porcelain crucibles (SUP-68281) with caps (SUP-68223), both from
Marienfeld (Superior, Laboratory Glassware, Germany), until whitish
ashes were obtained. The ashes were then solubilized with 2 mililiters
(mL) of HCl 6 Molar (M) (HCl, Merck a.g, analytical grade) and 2 mL of
HNO
3
1 M ultrapure (HNO
3
65%, Merck, a.g. distilled by sub boiling), over
a hot plate (< 80°C, Thermolyne, 48000 Furnace, USA).
The samples were ltered using Whatman ashless lter paper and
up to 25 mL with deionized, 18 Megaohm·centimeters
-1
(Mohm·cm
-1
)
water [34]. A blank containing only acid was included too. Total Fe,
Zn, Cu, Mn, Ca, Mg, Na and K contents were determined by atomic
absorption spectrometry (AAS, Perkin Elmer, Analyst 300, USA) with
either ame or emission. This system was equipped with a hollow
monoelement cathode lamp (Lumina Hollow Cathode Lamp, Perkin
Elmer, USA) for Ca, Mg, Na, K, Fe, Zn, Cu, and Mn.
For each analyte, adequate standard solutions of Ca, Mg, Na, K,
Fe, Zn, Cu, and Mn containing 1000 micrograms·mL
-1
(μg·mL
-1
) in 2%
HCl from Perkin Elmer (TruQTM grade, USA) were used, and a blank
was included for each analyte with 2% HCl. To avoid interference
in the measurements of Ca and Na, solutions of La2O3 and Al–Cs,
respectively, were dissolved in 2% HCl and used. An air–acetylene
ame was used with a ratio of 10-2.5, L·minutes
-1
(L·min
-1
). The limit
of detection (LOD) was calculated as 3 second·meters
-1
(s·m
-1
), where
was the standard deviation of 20 blank measurements divided by the
slope of the calibration curve. The limit of quantication (LOQ) was
calculated as 10 s·m
-1
.
Heme and non-heme Iron determination
For heme iron determination, Hornseys procedure was followed
[16] as adapted by Ramos et al. [34]. Briey, fresh meat samples (2 g)
were nely chopped and macerated in 9 mL of HCl–acidied acetone
in glass test tubes (Pyrex, N°9820, USA). Total heme pigments in meat
samples were determined as hemin after extraction with acidied
acetone solution. Hemin was quantied by its absorption peak at
640 nanometers (nm) in a spectrophotometre (Thermo Corporation,
California, USA). Heme iron content was calculated with the factor
0.0882 µg iron/µg hematin. Non-heme iron was determined as the
difference between total iron and heme iron content.
Statistical analysis
Data are presented as mean ± SEM for each rearing system, muscle
and sex studied (when differences were observed for sex). Main
effects, namely I, O with pasture, muscle and sex, were analysed
using an ANOVA with a GLM procedure and a post hoc Tukey–Kramer
multiple comparison test, with a signicance level set at P<0.05. The
data were analysed using the software NCSS (NCSS, 329 North 1000
East, Kaysville, UT 84037, USA, Version 2009).
RESULTS AND DISCUSSION
Productive parameters
As seen in TABLE II, differences between production systems in
age at slaughter, LW daily gain, and concentrate intake/live weight
gain ratio were observed. The growth of pigs in O system with pasture
was lower and age of slaughter signicantly higher than pigs in I.
Concentrate restriction applied to pigs could explain these results
[32]. When concentrate is not restricted, growth of pigs reared O is
higher than reared in I, as reported Juska et al. [20].
No differences in dorsal fat thickness or carcass yield between
systems were observed (TABLE II). In general, pigs fed pastures have
a lower performance, due to greater development and weight of
gastrointestinal tract [22]. For other hand, local breeds have a high
dorsal fat thickness (29-63mm) although this feature can be modied
TABLE II
Productive parameters and carcass characteristics
from Pampa Rocha pigs reared in an Indoor or
Outdoor with pasture production systems
Parameters
Systems
Indoor Outdoor P-value
Age of slaughter (days) 171.0 ± 1.36 183.1 ± 1.30 0.001*
Live weight (kg) 94.55 ± 3.63 91.50 ± 3.38 ns
Live weight gain (g·day
-1
) 801.2 ± 33.00 686.3 ± 31.60 0.02*
Concentrate intake /
live weight gain (kg/kg)
4.34 ± 0.16 3.85 ± 0.16 0.02*
Carcass weight (kg) 68.05 ± 0.68 66.30 ± 0.65 ns
Carcass yield (%) 72.00 ± 0.76 70.2 ± 0.72 ns
Dorsal fat thickness (mm) 28.45 ± 1.91 25.43 ± 1.83 ns
Values are mean ± SEM of n=11 (6 males, 5 females) for I and n=12 (8 males,
4 females) for O, for fattening period. Values of P<0.05 indicate signicant
dierences between production systems by ANOVA GLM. As sex eect was
no signicant means represents male and female together
Minerals in meat of local breed pig / Carballo et al. ________________________________________________________________________________
4 of 9
through the feed and the production system [1, 32]. Pasture intake
with a restricted concentrated diet improved the ratio of concentrated
intake: LW gain. This is important for little and medium scale farmers
that search lower production costs. No differences due to the effect
of were observed for any of the variables studied.
Mineral composition in concentrate and in the cultivate pasture
Concentrate and pasture mineral composition is show in TABLE III.
The botanical composition and the mineral content of the different
species of pasture varied with the sampling date. The high contribution
of Fe (mg·kg
-1
DM) in comparison to the concentrate stands out, similarly
to Mn. On the other hand, the concentrate had high levels of Cu, Zn,
and Mg compared to the three plant species that made up the mixture.
In general, the ryegrass showed lower contents of Fe, Mn, Cu, and Zn.
The contribution of Fe from Trifolium pratense was important with
respect to the other plant species, as well as to the concentrate.
Ramos et al. [33] reported higher Fe bioaccessibility in Trifolium
pratense than in Medicago sativa and Lotus corniculatus. Cichorium
intybus was observed in a higher percentage of the botanical
composition. This plant species is more preferred by pigs than the
other two [8]. Pasture intake (DM) represented 1.6% of LW in animals in
the O system during the nishing period. Rivero et al. [35] in a review,
TABLE III
Trace elements and macro mineral contents in concentrate and Trifolium pratense, Cichorium intybus, and Lolium multiorum, representing

Pasture Month*
Trace elements
Botanical
composition
Fe Zn Cu Mn
mg·kg
-1
dry weight
% Dry matter
Trifolium pratense
Jul. 1 1101.8 ± 59.3 28.6 ± 2.8 6.6 ± 0.8 134.7 ± 2.6 15.4 ± 5.2
Jul. 2 789.2 ± 31.1 24.8 ± 2.2 8.5 ± 1.5 129.5 ± 1.6 27.5 ± 3.4
Sep. 1 608.7 ± 28.4 29.8 ± 4.9 14.9 ± 1.6 112.0 ± 3.7 50.6 ± 5.7
Sep. 2 926.8 ± 55.3 15.7 ± 0.3 4.7 ± 0.5 128.7 ± 4.3 45.9 ± 8.6
Cichorium intybus
Jul. 1 738.1 ± 26.9 41.5 ± 5.3 8.6 ± 0.3 167.3 ± 4.7 65.7 ± 3.3
Jul. 2 560.0 ± 36.8 35.0 ± 6.5 8.1 ± 0.8 145.0 ± 10.5 53.9 ± 6.8
Sep. 1 577.7 ± 94.2 28.2 ± 2.5 12.4 ± 1.6 117.3 ± 8.7 36.3 ± 3.5
Sep. 2 728.0 ± 238.0 28.5 ± 1.1 12.9 ± 0.4 151.9 ± 19.7 38.8 ± 7.7
Lolium multiorum
Jul. 1 508.1 ± 48.7 10.1 ± 0.1 4.9 ± 0.4 111.8 ± 14.9 16.8 ± 3.3
Jul. 2 351.4 ± 52.5 8.2 ± 1.2 4.7 ± 0.6 88.8 ± 6.0 13.7 ± 3.3
Sep. 1 404.5 ± 67.7 10.9 ± 1.4 4.3 ± 0.8 72.3 ± 4.5 9.9 ± 1.8
Sep. 2 656.1 ± 207.5 8.7 ± 0.9 3.6 ± 0.7 72.4 ± 6.7 8.8 ± 2.9
Concentrate 188.5 ± 10.7 250.3 ± 17.8 38.2 ± 4.5 74.1 ± 3.5
Pasture Month*
Macro minerals
Botanical
composition
Ca Mg Na K
g
·100 g
-1
dry weight
% Dry matter
Trifolium pratense
Jul. 1 0.61 ± 0.01 0.25 ± 0.01 0.17 ± 0.01 2.45 ± 0.02 15.4 ± 5.2
Jul. 2 0.74 ± 0.04 0.27 ± 0.02 0.10 ± 0.01 2.44 ± 0.08 27.5 ± 3.4
Sep. 1 0.85 ± 0.01 0.26 ± 0.01 0.45 ± 0.01 2.43 ± 0.06 50.6 ± 5.7
Sep. 2 1.01 ± 0.01 0.30 ± 0.01 0.35 ± 0.01 1.58 ± 0.08 45.9 ± 8.6
Cichorium intybus
Jul. 1 0.72 ± 0.03 0.24 ± 0.01 0.30 ± 0.02 4.12 ± 0.23 65.7 ± 3.3
Jul. 2 0.63 ± 0.07 0.21 ± 0.02 0.24 ± 0.02 4.18 ± 0.30 53.9 ± 6.8
Sep. 1 0.90 ± 0.06 0.25 ± 0.02 0.56 ± 0.02 2.28 ± 0.09 36.3 ± 3.5
Sep. 2 0.97 ± 0.02 0.29 ± 0.00 0.99 ± 0.11 2.43 ± 0.26 38.8 ± 7.7
Lolium multiorum
Jul. 1 0.40 ± 0.01 0.19 ± 0.01 0.29 ± 0.01 2.92 ± 0.09 16.8 ± 3.3
Jul. 2 0.41 ± 0.01 0.18 ± 0.01 0.27 ± 0.01 2.74 ± 0.10 13.7 ± 3.3
Sep. 1 0.44 ± 0.01 0.19 ± 0.01 0.30 ± 0.01 2.85 ± 0.09 9.9 ± 1.8
Sep. 2 0.44 ± 0.02 0.21 ± 0.02 0.48 ± 0.03 2.51 ± 0.15 8.8 ± 2.9
Concentrate 0.92 ± 0.08 0.62 ± 0.01 0.41 ± 0.02 1.37 ± 0.10
Data represent mean ± standard error (SEM) of n=3 for each date of sampling or for concentrate. July and September 1 and 2 represents the initial
and nal dates for sampling during the fattening period of pigs in Outdoor production system