**2.2 Fatty acids composition and other compounds in muscle as an effect of acorns feeding**

The fatty acid composition of the diet reflects the quality of the tissue. Animals fed n-3 polyunsaturated fatty acids (PUFA) are a source of fatty acids in the human diet [25]. That is, by consuming meat from pigs fed on acorns and plants rich in n-6:n-3 fatty acids [26]. Several meat products reflect the diet of animals, such as fresh meats, sausages, cured meats, hams, and smoked meats, providing an unlimited range of highly appreciated flavors and aromas [27].

The evidence of an exclusive feeding of acorns in the animal diet is consistent in showing a higher lipid content (81.69% of total fatty acids) while feeding pigs with

#### *Quality of Pork Meat Fed with Acorns (*Quercus spp*.) DOI: http://dx.doi.org/10.5772/intechopen.108867*


*Ans: not significant*

*B ∑ Saturated fatty acids: C14 + C16 + C17 + C18 + C20*

*C∑ Monounsaturated fatty acids: C16:1 + C18:1n-9 + C18:1n-7*

*D∑ Polyunsaturated fatty acids: C18:2n-6 + C18:3n-3 + C20:2*

*E n-6:n-3: Fatty acids ratio (linoleic acid/linolenic acid)*

*F P:S: Polyunsaturated: Saturated fatty acids ratio*

*\*The p-value corresponds to the Student t-test between feedstuff and fresh acorn*

#### **Table 2.**

*Analyzed composition of feed (g/100 g) and fatty acid (mg/100 mg) [17] composition.*

grass and chestnuts (78.80% and 77. 62% of total fatty acids, respectively) have a lower fatty acid value [28, 29].

The highest percentages of monounsaturated fatty acids (MUFA), especially C18:1n-9, have also been found in diets rich in acorns [29], as well as in ham and loin muscles of Iberian pigs fed exclusively with acorns and grass in the fattening of montanera systems [30, 31].

Wild boars (*Sus scrofa*) raised with acorns had significantly (*P* = 0.0001) higher proportions of C18:1 *n-9* in *Longissimus lumborum* (LL) muscle than wild boars feeding with commercial concentrate, based mainly on corn [17]. There is a significant difference between pigs under free-range systems and confinement, as showed in **Table 3**.

According to Ref. [33], the hypothesis is that fatty acids composition depends on muscle type (oxidative or glycolytic), where a fasted period can be sufficient to decrease MUFA and n-6, but Ref. [26] suggests that a new experiment must have been made to verify this hypothesis.

The antioxidant composition effect also has been widely documented as the influence of feeding on the tocopherol content in muscle. γ tocopherol vitamin content of muscle acquired from free-range pigs is recognized in acorn feeding diets [31, 34]. The meat from these pigs is evidence of high quality [21]. Diet used in finishing phase (up to 155 kg body weight) is based on grass and acorn without restrictions [30, 31].

Chemical and antioxidant composition increase energy and fat levels in feed [17]. Some researchers showed negative protein digestibility because of acorn shells, especially on lysine amino acids [35–37].

It is important to consider that the values realized in the previous table, although they show high values of fatty acids, especially those MUFA and PUFA that contribute


*a ∑ Saturated fatty acids: C14 + C16 + C17 + C18 + C20.*

*b ∑ Monounsaturated fatty acids: C16:1 + C18:1n-9 + C18:1n-7.*

*c ∑ Polyunsaturated fatty acids: C18:2n-6 + C18:3n-3 + C20:2.*

*d n-6:n-3: Fatty acids ratio (linoleic acid/linolenic acid).*

#### **Table 3.**

*Fatty acid composition (mg/100 mg) of L. lumborum muscle from wild boars [17] and Iberian pigs [32] fed with acorns.*

#### *Quality of Pork Meat Fed with Acorns (*Quercus spp*.) DOI: http://dx.doi.org/10.5772/intechopen.108867*


*Values with different superscripts are significantly different using the Duncan test (P < 0.05).*

#### **Table 4.**

*Sensory characteristics of L. lumborum muscle from wild boars fed the experimental diets.*


#### **Table 5.**

*Cholesterol content in Semimembranosus muscle of the different karyotype groups (mg/100 g).*

to the concentration of essential fatty acids, come from intensive systems, which are becoming more and more relegated from the point of view of the consumer. In addition, it should be noticed that the free-range systems, where the Iberian pig predominates, also get outstanding values in meat at levels of essential fatty acids. The high sensory value from pig meat under extensive systems is attributed to essential fatty acids [38], especially in dry cured products with a strong flavor [19, 39, 40].

**Table 4** shows a descriptive sensory analysis made using a hedonic scale to reflect the perception by consumers of meat sensory characteristics from wild board fed with 20% and 40% of acorn diet inclusion. The Control group received a commercial concentrate base in corn. The consumers detected a positive relationship between the percentages of MUFA and PUFA with flavor, tenderness, and juiciness attributes. This is explained by the evidence that meat from animals fed with acorns was perceived as juicier and more tender by a sensory panel [17].

Differences in meat from wild boar compared to pork have been reported in particular considering cholesterol contents. In Brazil, Ref. [41] analyzed cholesterol in the meat of wild boar (2n = 36) and crossbreeds (2n = 37 y 38) founding lower cholesterol values in wild boards. Similar results were found in Ref. **Table 5** [42].

#### **3. Other values from feeding with acorn and sustainability systems**

Meat products derived from animals raised under extensive, free-range conditions, mainly feeding with acorns and grass in silvopastoral systems, as occurs, for example, in the Spanish system called montanera, comply with these requirements [32], and their high content of essential fatty acids makes it healthier than other animal products [43]. The extensive, free-range conditions contribute to the conservation of the dehesa ecosystem, where the extensive grazing system is a major determinant of biodiversity and ecosystem functioning in a forested Mediterranean grassland environment [44]. The environmental and economic importance of dehesas is due to their use in extensive free range and also to their characteristic high biodiversity [45]. This makes sense when the use of a site is done in a controlled manner,

especially when it is already known that grazing can have different effects on soil fertility and the communities of microorganisms, plants, and animals that develop from these soils depend on the local climate, topography, and physicochemical properties of the parent soil material [46], affecting soil fertility thought trampling and dung generating an easily litter degradation [47, 48].

The animals also remove the plant biomass, encouraging fast-growing species with high content of nutrients on their leaves and palatability [49]. On the opposite, the abandonment of free-range grazing leads to the existence of marginal areas grazing affects grassland dynamics, changing the species colonization and extinction relationships via consumption, mechanical disturbance, seed dispersal, and altered soil fertility due to dung-borne nutrient input [50]. Also, these sites are associated with a reduction in soil fertility-associated variables such as organic matter, total nitrogen, the availability of phosphorus [51], soil disturbance, carbon emission, and soil degradation [52].

There is an important point that stands out in the publication of Ref. [53], which is related to the sustainability of ecosystems, such as human impacts on the soil that remain unexplored. One potential source of anthropogenic soil carbon emissions is invasive species, with research suggesting that human-propagated animals ranging from insects such as mountain pine beetles and earthworms to herbivorous mammals, such as cattle, deer, goats, rabbits, and pigs, cause serious disturbances to soil properties through loss of vegetation and direct soil disturbance. They also evaluated the global ramifications of one of the most widely spread human species, wild pigs (*Sus scrofa*), on soil disturbance and CO2 emissions.

This makes sense since, although in Chile, wild boars are raised for commercial intentions in confinement conditions [54], however, an important part of the population lives free on the edge of the Andes Mountain range, from the region of Araucania to the Aysen region, in the heart of Chilean Patagonia [55].

The wild boar, an invader of South America [56], arrives in Chile in two ways, a direct importation from Germany and subsequent release in 1952 in the Villarrica National Park, and then by specimens that by their own means pass from Argentina from 1958 onwards [57]. It is an exotic species little studied, and only recently has it been published about its diet in southern America, focusing attention on the predation of birds and seeds of endemic trees (**Figure 2**) [55].

Their presence has a powerful impact, and often they could be responsible for the impoverishment of the local flora and fauna, as has happened in other places with invasive animal species [58, 59]. Management of wild boar population size in Chile is predominantly carried out by hunting at bait sites or by hunting dogs. The capture of live traps to latest keep them in confinement for meat production is another way of controlling the population. Wild boars and domestic pigs becoming from *Sus scrofa domesticus*. Wild boar can be reared in captivity.

The information found on the benefits of acorn-fed wild boar meat and the antecedents on the breeding of the Iberian pig in montaneras and Dehesas, very widespread agrosilvopastoral ecosystems in the Mediterranean ecosystems of the Iberian Peninsula, reveals an important alternative for the control of a species invasive within the Patagonian ecosystems. The economic and environmental importance of the Dehesas is because of the use of extensive livestock farming and also to their characteristic high biodiversity, the same livestock environment declared for the silvopastoral system's characteristic of southern Chile, where the wild boar lives.

Wild boar causes serious impacts on biodiversity and ecosystems in silvopastoral systems in Patagonia by affecting physicochemical soil and water bodies properties, plant diversity, predating on wild animals, seeds, and seedlings, destroying bird

#### **Figure 2.** *Wild boar Sus scrofa scrofa from Chillan city, Chile.*

nests, and interacting with fauna by competition, hybridization, and transmission of *Toxoplasma gondii* and *Trichinella spp.*, zoonotic and commercially important diseases [60–62] found that wild boar can cause economic losses in production activities because of the consumption of livestock offspring sprouts that feed cattle. In this way, the interspecific interaction between wild boars and other species can affect native ecosystems, but more studies are needed [63].

The incorporation of *Q. robur* into the Argentine Patagonian forest has been reported, standing out for its high productivity in forest environments where attempts have been made to diversify production systems and thus maintain the sustainability of the ecosystem. According to [64], *Q. robur*, at 150 years of age, reaches 25–30 m in height in the best sites in central Europe. In Patagonia, at 45–50 years, it reaches dominant heights of 20 to 24 m, which indicates that this species' turn would be well advanced.

There is a known conflict in the management of invasive species to conserve the ecological, social, and cultural values of the invaded ecosystems in complement to the use or utility of exotic species in productive activities [65]. As suggested by [63], management has become a complex issue that requires an interdisciplinary study with multiple approaches to develop an adaptive management strategy.

The vision of control of this species for economic and sustainable purposes of the environment will be an alternative to a meat organic farm system in an environment where extensive livestock is the pillar of the Patagonian agricultural tradition, and wild boars are one of the most damaging invasive species in the world, with a significant impact on the Patagonian forest degradation [66].

Meat production from wild boars in countries such as Chile has been increasing over the last decade, with an expanding demand both in Chile and overseas [67], for its benefits of being a meat product with healthy fatty acids and an alternative to contribute to the sustainability of the ecosystem.
