Effect of incorporating holm oak acorn in the feed of "Saanen" breed dairy goats in the wilaya of Batna

Sahi Sameh^1,2, Ouennes Houria^1,3, Bayoud Anouar² and Boukraa Malak²

¹ Laboratory of Animal Productions, Biotechnologies and Health, Institute Agronomic and Veterinary Sciences, Souk-Ahras University, 41,000, Algeria
sameh.sahi@yahoo.fr
² Chadli Bendjedid University of El Tarf. BP: 73, El Tarf 36 000. Algeria
³ Mohammed Chérif Messaadia University. Souk-Ahras 41 000. Algeria

Abstract

Our work is oriented towards the study of the impact of the incorporation of holm oak acorn on the quantity of milk produced and the valorisation of its effect in a diet in order to propose it as a supplement to the commercial concentrate. Three doses, all added to the same type of concentrate usually distributed, were tested and compared. 40 goats of the "Saanen" breed, raised extensively in the region of "Barika", wilaya of Batna, divided into 4 homogeneous groups of 10 goats each, took part in the experiment. They were all at the beginning of lactation, during the 8 weeks of the experiment, the quantity and composition of milk were measured weekly. In the last week of the experiment, milk production and composition were measured, analysed and compared. At 60 ^th day, the milk production varies according to the stage of lactation, it increases in the 4 ^th group of (3.03±1.65) l/d which presents the highest level of production, followed by the 3^rd group (2.23± 0.97) l/d and then comes last the control group (1) (1.43±1.87) l/d and within the same group according to the stage of lactation with a maximum amount of production in mid-lactation The results obtained show that the milk of the goats of the 4 ^th group is richer in fat (39.5 ± 0.01 g/l) and protein (34.5± 2.61) g/l than that of the goats of the other groups. The same variations were observed according to the stage of lactation. The valorisation of oak acorn in goat feed due to its high energy and unsaturated fatty acid content is a perspective resulting from an economic and nutritional necessity that should lead to a wide use of this forest product.

Key words: acorn Oak, Algeria, goat breed, milk production

Introduction

In agriculture, the goat, known for its hardiness and its particular adaptation has always been a very suitable solution for local populations who obtained almost all their milk needs from this animal. According to Alary et al (2011), goat farming is a means to achieve food security for populations living in extreme areas such as mountains. However, in Algeria, this breeding is still relatively anecdotal, goat milk, most often consumed or sold locally, but generally outside organized marketing channels and despite its importance for the dairy industry remains a relatively very little consumed and less processed locally with a production of 369,184,700 tons in 2017 (FAO 2019).

It turns out that one of the main obstacles to the development of goat breeding is the feeding of the herds, especially in the dry season when the combined effects of the increase in cultivated areas and the low quantity and quality of fodder production make it impossible to meet the needs of domestic animals (Morou and Diouf 2002).

Faced with this situation, it is more than necessary to find ways of managing the herds and feeding strategies that will allow the goats to overcome this lean period (Chehma et al 2002). The search for other locally produced foods such as oak acorns, barley, beans, etc., which can be used in animal feed, seems imminent in order to remove this dependence on foreign sources of production (Ait Saada et al 2017).

In this respect, the first objective of this work is to propose optimized rations in order to produce a maximum amount of milk per goat, from feed supplements and locally available resources using holm oak acorn as a supplement. Specifically, it aims to estimate the milk production of Saanen goats from monitoring data on the quantity and quality of milk produced, the share of holm oak in the feed ration and its influence on milk production, and to propose solutions to improve the feeding of the herds.

Materials and methods

Pre-experience

The acorns of holm oak (Quercus ilex) were collected the end of November of the year 2020 in the forest massif of Barika of the wilaya of Batna-Algeria (Map 1.), crushed and mixed in accordance with the standard in a mixing mill. We used commercial concentrate in addition to the straw.

Map 1. General presentation of the wilaya of Batna

In order to estimate the digestive value of holm oak, 04 goats were used in a pre-experiment (figure b2), two of them (control) received their usual daily ration containing 400 g of the concentrated feed. The 2 other goats consumed almost the same ration (100 g/d of holm oak was added to the concentrate feed) for 15 days.

The analysis methodology was based on a daily visual examination of these goats. The adaptation period of the goats allowed us to determine the minimum quantities of holm oak acorn to be distributed. All remarks and observations made regarding the feeding behaviour of the animals during this period were taken into consideration.

Choice of animals

40 Saanen goats, a quarter of them primiparous, chosen on the basis of their age, live weight and number of days in milk (DIL) at that time, were selected to form four experimental batches of 10 goats as homogeneous as possible.

The breeding system practiced is the extensive system. The goats are fed mainly on pasture. These 4 groups were removed from the herd, differentiated by different coloured collars and separated in 4 different pens, in order to test and compare 4 concentrate mixtures (table 1).

Photo 1. "Saanen" goats used in pre-experience

Experience

The "Control" ration was the one usually distributed to the goats in winter, and consisted of silage distributed in the morning before grazing (composed of straw from natural pastures. Their vegetation is essentially composed of grasses, legumes associated with crucifers (field mustard), supplemented by a daily distribution of 2.5 kg of commercial concentrate (the concentrate composed mainly of crushed barley, wheat bran, soybean cake and CMV (vitamin mineral supplement) with respective proportions of 80, 10, 7, 3%) per goat in the evening. Only the concentrate mix changed per day (table 2). Water is provided ad libitum. The rations were distributed in 2 meals/day. Forage was distributed collectively at the trough while concentrates were distributed individually at milking. During the meals, the feeds were distributed sequentially and the refusals were removed before the next feed was distributed.

Measurement and sampling

The quantity of milk produced was measured before the experiment, to form the groups and then during each morning and evening milking to represent the daily production of each goat. The composition of the milk produced by each batch was determined with the help of a "Lactoscan" apparatus which is a modern chemistry analyzer adapted to the analysis of each type of milk. It allowed us to obtain precision in the measurement of the different parameters. The results of the analysis are displayed on the screen within 75 seconds.

Statistical analysis

The data were subjected to descriptive statistics (mean, standard deviation, chi-square test) and comparison of means (Student's t test) using SPSS software, analysis of variance (ANOVA) with the Newmankeuls multiple comparison test. The significance level used is p <0,05.

Results and discussion

The acorn of the holm oak is a very important nutritional source for ruminants and poultry (table 3)., it is an energetic food given its richness in starch (Afraitane 1990), it is poor in vitamin B1, B2, which are relatively 2.1 mg ⁄kg and 0.8 mg ⁄kg respectively (Belarbi 1990).

The fat content of holm oak acorns reported in the literature is very variable (Table 4). variable (table 4). It seems that the Algerian acorn varieties are richer in lipid. This particularity is likely to influence favorably their energetic efficiency but can be harmful to their conservation (Bouderoua 1995). The lipid content of green oak acorn varies from 7 to 14.4%.

The analysis of the fatty acids by gas chromatography showed that the lipids of the acorn of holm oak contains 83.3% of unsaturated fatty acids of which 65.5% of fatty acids mono unsaturated fatty acids (MUFA) and 17.85% of poly unsaturated fatty acids (PUFA), this composition provides the essential fatty acids w3 and w6 which are essential to life with a PUFA∕AGS ratio is 1.07 (Benguettaf and Benaouda 2012).

Tannins exist in significant quantities next to carbohydrates, especially in green fruits during ripening, they disperse at the same time that sugars accumulate. The tannin contents make it possible to affirm that the Algerian species of acorn of holm oak and cork oak are usable in animal feed without potential risk of intoxication. (Boudroua 1995).

As the goats were in early lactation during the experiment, the proposed rations were designed to cover the production requirements based on the forages they usually fed. Concentrated feed was replaced, in part, by crushed holm oak acorn. Three doses were considered, and a pre-test was carried out at the beginning to get an idea of the digestive value of these.

The transition from the usual concentrate to another was not an easy task. The goats had never tasted the tested feeds before the experiment. It seems to be difficult to introduce new feeds to adult goats that have never tasted them before.

The comparison of milk production in experimental and control goats, and taking the amount of milk/day as the unit, shows the significant effect of holm oak acorn on milk production. The milk production in both groups of goats (G3 and G4) is quite high (3.03±1.65 and 2.23± 0.97) l/d respectively (table 5).

At the end of the experimental period, we notice that there is generally a stabilization in milk production with a remarkable variation. This stabilization can be explained by the abundance of alfalfa during this period with the adaptation of the animals to the new diet (acorns of holm oak).

Optimizing herd management involves creating a herd or batches of homogeneous animals that allow for rigorous management of lactation, culling and dry period days. Homogeneous batches make it possible to adapt the ration to provide energy and protein intakes that are best suited to the needs of the animals in the same batch, thus avoiding waste thanks to better use of feed, particularly available forage. Homogeneous batches can be made on the basis of calving and breeding periods, age, milk production, body condition, etc. (Bossis et al 2016).

The average daily milk production (DMP) obtained in the goats of the 1 ^er group at day 60 ^th is 1.43±1.87 l/d (table 5), which is much lower than the value of 4 ^th group at the same period (3.03±1.65) l/d (figure 1). Similarly, this average DIL is higher than that of local Algerian breeds producing (1.50 and 2.56) kg/d for Arbia and M'Zabite goats respectively (Mouhous et al 2016). Our results are similar to the results reported for local Tunisian goats (Mahouachi et al 2012).

Figure 1. Amount of milk produced during the experimental period in goats (l/d)

Milk production in general depends on the genetic potential of the animal and its diet. It is known that a good dairy goat that is poorly fed produces little. Therefore, according to the experimental protocol, the adaptation period can be explained by a variation of parameters that can directly influence the milk production of this breed, mainly the stage of lactation, the milking system and the feeding.

The use of acorn as a supplement with concentrate can be explained by its availability. Thus, it is used by the inhabitants for human consumption and not as a concentrated supplement in goat feed. While this commercial supplement is used to a lesser extent, cereal grains (millet, maize, sorghum) are not even used by farmers due to their high cost or competition (Boye 2008).

Already in ancient times, before the generalization of cereals, bread made from this pulverized fruit was the preferred food of the European population (Jimenez et al 1977). North American Indians nowadays consume oak acorns in the form of porridge, bread and cakes. In North Africa there is still some consumption of acorns as a harvested product (Mebarki 2020).

In Algeria, the cotyledons are either consumed as a dry fruit or integrated in the manufacture of couscous, a dish much appreciated by the native population. Being an energy food of the first order, rich in particular in starch, the acorn has always been used, from the part of the world, in animal feed and served to different domestic animal species to produce meats very appreciated by consumers: pigs, sheep, cattle, poultry...etc. (Ait saada et al 2017).

In Algeria, the holm oak occupies a very large part of the forest surface; it is found everywhere, especially in the western part. The Algerian oak groves extend all along the Tellian atlas, they are estimated at 1,128,103 Ha (Romane and Terradas 2013), extend mainly, in the eastern and central regions. They occur in scattered areas in the western region of Algeria.

In this sense, several studies conducted by Algerian researchers have shown the interest of using holm oak acorns in animal feed, focusing on the nutritional properties of raw or autoclaved acorn-based diets (Bouderoua et al 2003; Bouderoua et al 2005).

Studies were undertaken on broiler chicken by Bouderoua et al (2005) and interesting results were obtained on the zootechnical performances, nutritional and dietetic qualities of white meat which are characterized by lean carcasses and an acceptable yield at slaughter. It was found that the acorn of holm oak intended for the chicken diet has interesting contents of unsaturated fatty acids. Bouderoua et al (2009) report that acorns are an interesting nutritional source for poultry and ruminants.

According to Mekki et al (2018), the substitution of 40% of barley in the concentrate feed by holm oak acorn did not result in an effect on lipid oxidation and meat colour parameters of lambs. Keddam et al (2010) proved that the use of holm oak acorn in sheep feed is very suitable for improving the health value of lamb meat.

Meuret (2003) reports that the leaves are also used and fed fresh to goats on pasture or range. Ouazani et al (2014) found that the acorn diet of holm oak for lambs contains 24.3% C18:2; 1.3% C18:3 and 54% C18:1. The effect of oak acorn incorporation on the fatty acid profile of broiler chicken has been shown to enrich the meat in PUFAs (Hamou et al 2012; Bouderoua et al 2009; Sisbane 2009).

The study of the pericarps of holm oak (Quercus ilex) acorns, rich in sources of parietal polymers such as polysaccharides, can form the basis for further work devoted to the valorization of plant by-products of interest in the field of bio sorption. These by-products have the advantage of being both sources of parietal polymers and a very efficient biosorbent (Mebarki et al 2019).

The analyses of physicochemical parameters of milk are shown in Table 6. The values obtained for the milk in question are largely within the range advanced by several authors Aguera et al (2005) and Noutfia et al (2011).

We observe that the value of titratable acidity is very close for the first three groups that is between 18.2 °D and 16.55°D, however the average protein and lactose content for the 4 ^th group is (34.5± 2.61) and (50.8 ± 0.80) respectively.

According to Aboutayeb (2009), a fresh milk can have as acidity between 15 and 18 °D and FAO (2010) reports that the acidity of milk is on average 16 (15-17 °D). The average values of titratable acidity of milk studied are in agreement with Labioui et al (2009). The average of 17 °D remains however in the range of 15 - 17.5 °D of raw milk. On the other hand, the results are identical to those found by Noutfia et al (2011) after a statistical study of goat milk.

Remember that titratable acidity = natural acidity + developed acidity. The constituents of milk that contribute to natural acidity are phosphates (0.09%), caseins (0.05 - 0.08%), other proteins (0.01%), citrates (0.01%) and carbon dioxide (0.01%). To this natural acidity is added the developed acidity which is the result of a development of lactic bacteria that form lactic acid by fermentation of lactose (Ghaoues 2010).

The values of density vary between 1029.46 ± 0.60 and 1036.2 ± 0.6, are higher than those of milk studied by Labioui et al (2009) which is 1028. The density depends on the content of dry matter, fat, the increase in temperature and food availability. The same is true for fat (between 3.63% and 4.56%).

The fat is more remarkable in the 4 ^th group with (3.95 ± 0.01)% then the 3^rd group with (3.73± 2.0) % (figure 2). The value of fat is higher compared to that found by Roudj et al (2005) which is 1% in the region of Oran in western Algeria, but it is low compared to that found by Boubezari (2010) for the local breed in Jijel (4.63%) and Benyoub et al (2018) which is 5.25% in goats from the Chouli region.

Figure 2. Physico-chemical composition of milk produced

The type of feed provided influences the composition of the milk. Thus, energy rations do not allow the production of acetyl compounds, which contributes to a decrease in milk fat content (Morel et al 2006). Lipids are the most important components of milk in terms of cost, nutrition, physical and sensory characteristics they confer to dairy products (Park et al 2017).

They are very rich in lipids also, this feature has a favorable impact on the energy level. According to Serment et al (2010), raw milk production should increase with increasing energy content of the ration, when energy is limiting, without impacting TP, as protein secretion increases, but diluting TB as MG secretion remains stable.

Ideally, the pH should never fall below 6.2 for more than 4 hours a day. If the rumen becomes too acidic, propionic acid increases at the expense of acetic and butyric acid. These last two volatile fatty acids are precursors of milk fat. This change in proportions is deleterious because it reduces the TB of milk, which can lead to a "reversal of rate". Maintaining a stable pH between 6.2 and 6.8 in the rumen therefore ensures a better milk TB (Legarto et al 2014).

The dry extract varies between 130 ± 4.76% and 131± 5.41% and the ash varies between 0.64 and 0.66%, the dry matter content of the milk of the four groups is comparable compared to the contents of 11.5% and 10.2% recorded by Moualek (2013) for goat milk of the wilaya of Tizi-Ouzou. The mode of management of the herd, the level of feeding, are the main factors of variation in the production and composition of milk (Kouniba et al 2007).

The values of protein very close to each other, are inferior by contribution to that found by Benyoub et al (2018) which is 4.3 %. Raynal-Ljutovac et al (2008) with 2.6 %, marks the similarity of the total protein contents of our samples. Then averages such as 3.5 % (Decandia et al 2007) and 3.84 g % (Zahraddeen et al 2007) slightly confirm our results in protein matter.

Bouderoua et al (2003) show that the acorn of the holm oak is rather poor in protein (less than 8%). This constituent remains nevertheless not negligible, compared to cereal foodstuffs. The protein solubility gives information on the degree of digestibility of the nitrogen contained in the acorn, it is on average between 65% and 68%. The more mature the acorn, the better the protein solubility. Crude protein is only slightly present. The different contents of these components are probably related to the variety, the geographical area, the nature of the soil and the storage conditions.

Regarding the freezing point, the milk from the four groups visited characterized by a freezing point that varies between -0.52 ° C and -0.59 ° C, these values show that the freezing point of our samples is significantly lower than the averages recorded in other breeds of goats, this can be explained by the high rate of fat and protein, the increase in the value of freezing point is an index of wetting an increase of 0.005 ° C corresponds to about 1% of foreign water (Rosenman and Garry 2010).

The comparison of the average values of the milk produced showed a significant difference between the biochemical and physico-chemical composition of the milk of the goats of the 1^st and 4^th group for all the parameters.

Adding concentrates to the ration increases milk production, and therefore income, but sometimes not enough to compensate for the increase in feed cost. It may be more interesting to produce less milk but to save on purchases. Another way to increase the profitability of your farm is to adjust the ration.

Distributing a precision ration, in line with the animals' needs, ensures good animal health, limits waste and adjusts the distribution of concentrated feed (Wattanachant 2018). Finally, herd management is also done through animal selection: the animals chosen must have production capacities adapted to the desired production and must be able to valorize the available feed (Bossis et al 2016).

The daily secretion of MG in milk was different between groups. According to Serment et al (2010), it should have remained stable when the energy content was increased. In this experiment, MG secretion was higher in the "4" group than in the "control" group. The increase in lipid secretion may be related to the dietary fat content. The dietary fat content of holm oak acorns reported in the literature is highly variable. It seems that the Algerian acorn varieties are richer in lipid (Foudhil 1990; Belarbi 1990). This particularity is likely to have a favourable influence on their energy efficiency but may be detrimental to their conservation (Bouderoua 1995). The lipid content of holm oak acorns varies from 7 to 14.4% (Benguettaf and Benaouda 2012).

In our country, if a development effort continues, the production of goat milk will be on the rise, which gives very important prospects for the consumption and sale of this milk in a fresh state or its processing into cheese, but its costly obtaining remains a major constraint on its use, especially with the increase in demand for cheese. It is up to the public authorities to put in place the ways and means necessary for the exploitation of this resource, where it has been shown that it is quite possible to replace the commercial concentrate, especially imported at a cost of foreign currency.

Conclusion

This experiment was carried out in response to the desire of goat farmers to provide their goats with rations of sufficient quantity and quality throughout the year.

The acorn of the holm oak was used as an alternative complement to the concentrate, an energetic food of the first order, being rich in starch and lipidic fraction, which did not exert any toxic effect in the goats during the breeding experiment.

The study showed that it is therefore possible to add these acorns, without autoclaving, in their raw state, to 40% of commercial concentrate, improving production performance.

This valorization of acorns in goat feed opens a very interesting opportunity to produce in Algeria a goat milk in quantity and quality.

Acknowledgments

The authors would like to acknowledge all breeders for their help and support.

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