Substitution of corn and soybean oil by cassava meal and African palm tree oil in diets of laying hens

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175 Cuban Journal of Agricultural Science, Volume 46, Number 2, 2012. Substitution of corn and soybean oil by cassava meal and African palm tree oil in diets of laying hens J. B. Zacarias1, M. Valdivié2 and S. J. Bicudo3 1 Universidad “José Eduardo Dos Santos”, Huambo-Angola Instituto de Ciencia Animal, Apartado Postal 24, San José de las Lajas, Mayabeque, Cuba 3 Universidad Estadual Paulista (UNESP) Botucatu, Sao Paulo, Brasil Email: baptista74@yahoo.com.br 2 Fourty-two White Leghorns laying hens, from the commercial Cuban hybrid L-33, were used for eight weeks during the laying peak (36 to 43 weeks of age), to assess the substitution of corn by cassava root meal (Manihot esculenta Crantz) and the crude soybean oil by crude oil of African palm tree (Elaeis guineensis J.) in the diets of laying hens. Analysis of variance was conducted, according to simple classiication design, with three treatments and 14 repetitions (a cage with a hen). The treatments consisted of three diets (1- corn meal + soybean oil; 2- 25 % cassava meal + African palm tree oil; 3- 53 % cassava meal + African palm tree oil), with 15.71 % CP; 3.83 % Ca and 0.36 % P available. The viability was of 100 % in all treatments. No differences were found for laying (92.21, 92.09 and 91.59 %), which surpassed the potential of this hybrid during the laying peak (90 %), conversion (118g feedstuff/egg in the three treatments), egg mass produced (3066, 3114 and 3071 g/bird) and mass conversion (1.99, 1.95 y 1.98 feed consumed/egg mass). The pigmentation of the egg yolk was reduced as the level of cassava meal increased in the diets (6, 4 and 3 at Roche’s scale), as well as the cost of the feed consumed in 56 d per hen (2.56, 2.15 and 1.83 USD/bird). The possibility of substituting, totally, corn meal by that of cassava and soybean oil by that of the African palm tree in the diets of laying hens during the laying peak was determined, with positive economic effect and without damaging the productive performance of birds. Key words: cassava, African palm tree, laying hens. The Agriculture Ministry of Angola (MINADEP 2007) indicated that the feeding balance of this country has deicit of cereal, at a rate of 54 %, due to the low production levels and the climatic irregularities of those potentially cereal producer areas. In this context, the country has to import from the South African market in order to satisfy the demand of these feeds for the human and animal consumption through the importation of corn and soybean oil to high prices (FAO 2010). The cassava root production in Angola surpasses the 10 million of tones/year, satisfying in 242 % the needs of the human consumption (MINADEP 2007, FAO 2010 and FAOSTAD 2011). Therefore, cassava root has potentialities to be used in animal feeding, as a substitute of corn and other cereals. The avian nutrition studies of Díaz and Valdivié (1999), Gil and Buitrago (2002), Bautista et al. (2003), Valdivié et al. (2008), Bernal et al. (2010) and Valdivié et al. (2011) indicate that. The African palm tree (Elaeis guineensis J.) is autochthonous from Angola. The oil from its fruit has been traditionally used in the country for human consumption. It is included in the group of the most important twenty products produced in the country (UCV 1985 and FAO 2010). From the last decades of the last century, the African palm tree oil has been used a great scale in bird feeding, substituting other plant oils of higher costs (Oloyume and Oyenuga 1973, Oloyume and Okunaga 1975, León et al. 1985, Leeson and Summers 1991, Gil et al. 2001, Pesti et al. 2002, Hake et al. 2005, Cruz et al. 2006 and Isika et al. 2006). This research was conducted to validate the substitution of imported corn and soybean oil by cassava meal and African palm tree oil in the diets of laying hens during the laying peak. Materials and Methods The experiment was conducted in the poultry facilities of the Institute of Animal Science, between October and December 2010. Fourty-two White Leghorns laying hens of the hybrid L-33 and 36 weeks of age, during the laying peak with 90 % laying or more. The birds were located in three treatments, consisting of three diets: irst or control, with corn as basic energy source plus soybean oil (1- corn + soybean oil); second, the corn was partially substituted by the inclusion of 25 % of cassava root meal and the soybean oil by African palm tree oil (2- 25 % of cassava + 2.5 % of African palm tree oil); third, the corn was totally substituted by the cassava root meal and the soybean oil by African palm tree oil (3 53 % of cassava + 2.5 % of African palm tree oil). The composition, contribution and prices of the diets are shown in table 1. The cassava root meal used had 87.79 % DM; 2.19 % CP; 0.47 % EE, 74.84 % starch; 5.26 % simple sugars and 10.7 ppm of cyanhydric acid. The analyses were conducted in the Tropical Root and Starch Center (CERAT) of the State Paulist University (UNESP), in Sao Paulo, Brazil, according to AOAC (2000). The ME selected for the African palm tree oil was of 36855.1 MJ /kg and 13958 MJ/kg for the cassava root meal, values recommended by Rostagno et al. (2005) for those two feedstuff raw materials. The hens were located in individual cages, of 176 Cuban Journal of Agricultural Science, Volume 46, Number 2, 2012. Table 1. Composition of the diets, contributions and prices Ingredients, % Corn meal Cassava root meal Soybean cake African palm tree oil Soybean crue oil Premixture Monocalcic phosphate Calcium carbonate Common salt DL-methionine L-lysine BHT (butylated hydroxytoluene) Choline chloride Contribution crude protein, % ME, MJ/kg Calcium, % Phosphorous available, % Lysine, % Methionine + Cystine, % Threonine, % Tryptophan, % Crude ibre, % Cost/t (USD/t) United States Dollar (USD) Treatments 25 % cassava meal + 53 % cassava meal + 2.5 % 2.5 % palm tree oil African palm tree oil 31.53 25.00 52.89 28.92 32.74 2.50 2.50 1.00 1.00 1.24 1.23 9.24 9.05 0.25 0.25 0.28 0.31 0.01 0.01 0.01 0.02 0.02 15.71 15.71 11336.02 10838.07 3.83 3.83 0.36 0.34 0.85 0.91 0.77 0.77 0.54 0.55 0.18 0.19 3.50 4.60 355.23 302.15 Corn + soybean oil 60.00 25.5 2.43 1.00 1.21 9.34 0.25 0.22 0.02 0.01 0.02 15.71 11704.00 3.83 0.36 0.85 0.77 0.56 0.18 2.40 423.00 40 cm x 40 cm, with two drinkers for water ad libitum and a lineal feeder, of 40 cm of longitude, with 108 g of feedstuff/bird/d and 16 h of light. Table 2 shows the daily amount of nutrients and ME given to the hens in 108 g of feedstuff/bird. Analysis of variance, according to completely randomized design, with three treatments and fourteen repetitions was conducted (an individual cage with one hen). The differences between means were tested according to Duncan (1955). The birds had two weeks for adapting to the diets (34 and 35 weeks of age), and then they were examined for eight weeks (56 d). The daily intake (feedstuff, nutrients and ME) was determined, as well as the individual live weight (at 36 and 55 weeks of age), daily egg production, individual weight of the eggs (once a week), broken eggs (daily), eggs without shell (daily), eggs with double yolk (daily) Table 2. Nutrients intake and metabolizable energy Nutrient or metabolizable energy Feedstuff, g/bird/d ME, g/bird/d CP, g/bird/d Methionine + Cystine, mg/bird/d Lysine, mg/bird/d Threonine, mg/bird/d Tryptophan, mg/bird/d Calcium, g/bird/d Phosphorus available, mg/bird/d Corn + soybean oil 108.0 302.0 16.97 832.0 918.0 605.0 194.0 4.14 389.0 25 % cassava meal + 2.5 % African palm tree oil 108.0 293.0 16.97 832.0 918.0 583.0 194.0 4.14 389.0 53 % cassava meal + 2.5 % African palm tree oil 108.0 280.0 16.97 832.0 983.0 594.0 205.0 4.14 389.0 Cuban Journal of Agricultural Science, Volume 46, Number 2, 2012. and yolk pigmentation of 12 eggs (at 55 weeks of age) from the last Wednesday. The Roche’s fan was applied. The following indicators were calculated with these elements: mass of eggs/bird, mass conversion and feedstuff consumed (g/egg produced). The economical analysis was conducted from the different prices of the feeds consumed, which was the only variation between treatments. The prices of feedstuff raw materials in Angola (USD/t) were obtained from the FAO (2010) reports: corn (397), cassava root meal (195), soybean oil (1316), African palm tree oil (422), soybean cake (430), premixture (1649), monocalcic phosphate (578), DL-methionine (5716), L-lysine (2676), BHT (1906), choline chloride (1259), calcium carbonate (56) and common salt (360). Results and Discussion Viability was of 100 % in all treatments, showing that the partial or total substitution of corn by cassava root meal, and that of soybean oil by African palm tree oil does not cause the death of the laying hens. The studies of Tanasrisutarat et al. (2002), Saentaweesuk et al. (2002) and Cruz et al. (2006) prove so. These authors indicated that, when substituting corn by cassava root meal, the losses due to mortality are reduced in more than 50 %, because of the positive effect of the low content of cyanhydric acid on the gastrointestinal health, when reducing the harmful microorganisms and favoring the growth of lactobacilli and yeasts. Table 2 shows the feedstuff and nutrients consumption. That amount was offered to the birds everyday and they consumed it all. The hens consumed in all treatments the same amount of CP/bird/d, of methionine + cystine, and of calcium and phosphorous available per bird/d. This satisied the needs of these nutrients in the White Leghorns laying hens during the laying peak, according to Rostagno et al. (2005), HyLine (2006) and UECAN (2010). The ME content in the diets was reduced with the use of cassava root meal as the feedstuff vegetal oil did not increase in order to cheapen its cost. Therefore, the intake was reduced from 1262.4 MJ/bird/d to 1170.4 MJ, when substituting totally the corn by cassava root meal. This may not damage the birds’ performance, according to HyLine (2006). This author recommends daily intakes from 1149.4 to 1195.5 MJ of ME/bird. As synthetic threonine and tryptophans were not supplemented, the daily intakes of the first were somehow reduced (table 2), when corn was totally substituted by cassava root meal, involving only the requirement established by Rostagno (2005) in the control treatment with corn. The daily requirements of threonine, set by UECAN (2007), of 702 mg/bird/d, did not satisfy the two treatments tested. Therefore, further investigations on these feeding systems with 177 cassava root meal supplemented with synthetic threonine are necessary. It is also suggested the revision of the requirements indicated by the authors cited, as they seem to be excessive. When corn was totally substituted by cassava root meal, the lysine intake increased, as the concentration of soybean cake in the diet augmented. According to Rostagno et al. (2005), the soybean cake is rich in lysine. Oke (1978) and García and Dale (1999) informed that levels of cassava root meal over 25 % could reduce the feed intake and affect the birds’ performance, due to the dust effect that could provoke the cassava root meal on the balanced feedstuffs. For that reason, more than 20 to 25 % is not included in the diets in the countries of the European Union. However, the diets used in this study had 2.5 % of African palm tree oil and it eliminated the dust effect. First-quality cassava meal was used in this experiment, with 74.84 % of starch. As shown in table 3, the eggs production during the eight weeks of the laying peak did not differ signiicantly between treatments, and surpassed 90 % of laying during the whole experiment. That is, it allowed the L-33 Cuban laying hens express or surpass the maximum laying for this hybrid during the best laying peak (90 %), according to data of UECAN (2000). It has been proved that the total substitution of corn by cassava root meal and soybean oil by that of African palm tree during the laying peak, allows the laying hens to express ther maximal potential of egg production. This result coincides with that obtained by Pillai et al. (1968), Enrique and Ross (1972), Hamid and Jalaludin (1972), Montilla et al. (1973), Portal et al. (1973), Muller et al. (1974), Khajarern et al. (1979), Tewe and Egbunique (1992), Wood (1992), Ávila (1996), Tewe and Bokanga (2001) and Cruz et al. (2006), who used lipid sources in their diets. These sources reduced the dust effect, without damaging the feed intake, when using cassava meals with high content of starch and low of cyanhydric acid. The study also showed that the L-33 Cuban laying hen can express its maximal potential of egg production (90 % or more) during the laying peak, with daily intakes/bird: 16.97 g of CP; 1262.4 to 1170.4 MJ of ME; 832 mg of methionine + cystine; 918 mg of lysine; 605 to 594 mg of threonine; 194 to 205 mg of tryptophan; 4.14 g of calcium and 389 mg of phosphorous available. The amount of feeds per egg produced was of 118 g of feedstuff/egg, that is, very eficient and did not differ between treatments (table 3). The average weight of egg was superior to that of the control (corn + soilbean oil) in the diet where corn was totally substituted by cassava meal + African palm tree oil. There is no an obvious explanation for this, although Isika et al. (2006) obtained higher weight of the eggs when using African palm tree oil as basic source of lipids in the young animals. This result was associated to a higher yolk synthesis due to the fatty acids (particularly 178 Cuban Journal of Agricultural Science, Volume 46, Number 2, 2012. Table 3. Performance of laying hens, of 36 to 44 weeks of age Indicators Levels of cassava root meal and African palm tree oil 25 % cassava meal 53 % cassava meal + Corn + + 2.5 % African palm 2.5 % African palm SE (±) soybean oil tree oil tree oil 100 100 100 51.64 51.57 51.29 0.95 92.21 92.09 91.59 1.69 118.14 117.71 118.36 2.29 59.40a 60.40c 59.90b 0.09*** 3066.0 3114.0 3071.0 57.0 1.99 1.95 1.98 0.04 Viability Number of eggs/bird % of laying Grams of feedstuff/egg Egg weight Egg mass Mass conversion (g of feedstuff/g of egg) Yolk color 6 4 3 a,b,c Means with different letters in the same row differ at P < 0.05 (Duncan 1955). ***P < 0.001 oleic acid) offered by the palm tree oil (Oloyume and Okunuga 1975 and Scragg et al. 1987). The palm tree oil, for being rich in oleic acid, can be as effective for increasing the egg weight as an oil with abundant linoleic acid. According to these authors, the oleic acid is as effective as the linoleic to increase the egg weight. There were no broken eggs or with double yolk in any treatment and there were no eggs without shell. This shows a good nutritional balance in all the experimental diets, mainly in favor of a proper balance of calcium and phosphorous available. These elements, together with vitamin D, determine the quality of the egg shell (NRC 1994, Rostagno et al. 2005 and Acosta 2009). The color of the egg yolk was reduced according to the Roche’s fan, when corn was substituted by cassava meal. This is because of the low content of carotenoid pigments of the traditional cassava root (Ravindran and Blair 1991 and Cruz 2006). This can be solved by adding natural or industrial carotenoid pigments (García and Dale 1999 and Valdivié et al. 2008). Table 4 shows the variation in the daily intake of raw materials for feedstuff, when corn was substituted by cassava root meal in the diet for laying hens. There was an increase in the intake of cassava root meal, soybean cake, monocalcic phosphate and DL- methionine. Corn intake, calcium carbonate and L-lysine were reduced, which is good from the economic point of view. The same happened when soybean oil was substituted for that of African palm tree. In this case, the cost of the feed consumed per animal during the 56 d of test was 0.73 USD/bird, cheaper compared with that of cassava root meal + African palm tree oil, when comparing with that of the control of corn + soybean oil (table 4). The economic effect of this treatment is a saving of 4.76 USD/hen/year, so in every million of laying hens applied, the repercussion will be of 4.76 millions of USD. In the treatment with 25 % of cassava root meal, the cost of the feed consumed per hen during the 56 d of test was 0.41 USD/bird cheaper than the control. This inluenced positively when applying it in a great amount of hens. Table 4. Intake of raw materials for feedstuff/bird/d and economic effect Raw material Corn, g/bird/d Soybean oil, g/ bird /d Cassava meal, g/ bird /d Palm tree oil, g/ bird /d Soybean cake, g/ bird /d Monocalcic phosphate, g/ bird /d Calcium carbonate, g/ave/d DL-methionine, mg/ave/d L-lysine, mg/ave/d Cost of food intake in 56 d, USD/hen Corn - soybean oil 64.80 2.62 27.54 1.31 10.09 236.00 22.00 2.56 - 25 % cassava meal + 2.5 % African palm tree oil 34.05 27.00 2.70 31.23 1.34 9.98 302.00 11.00 2.15 Cassava meal + 2.5 % African palm tree oil 57.12 2.70 35.36 1.33 9.77 335.00 1.83 Cuban Journal of Agricultural Science, Volume 46, Number 2, 2012. The possibility of substituting totally corn by integral cassava root meal and soybean oil by that of African palm tree during the whole laying peak was demonstrated, although the substitution of corn by integral cassava root meal diminished the pigmentation of the yolk egg. This result represented a saving of 3.58 USD/hen/year. References Acosta, A. 2009. Evaluación de una fuente de fósforo nacional y enzimas itasas en la respuesta productiva-metabólica de pollos y gallinas ponedoras. PhD Thesis. Instituto de Ciencia Animal. San José de las Lajas. La Habana. Cuba. 133 pp. AOAC. 2000. Oficial Methods of Analysis. 17th Ed. Assoc. Anal. Chem. Arlington. Virginia. USA Ávila, E. 1996. Utilización de fuentes energéticas en la producción de piensos balanceados. Segundo Simposio de Nutrición Animal México-Cuba. La Habana. Cuba Bautista, E.O., Ramírez, W. & Barruela, D. E. 2003. Utilización de la harina de equilibrium value of MeCpG steps (,+14 deg.) [31,44]. In comparison, methylation has a significantly lower stability cost when happening at major groove positions, such as 211 and 21 base pair from dyad (mutations 9 and 12), where the roll of the nucleosome bound conformation (+10 deg.) is more compatible with the equilibrium geometry of MeCpG steps. The nucleosome destabilizing effect of cytosine methylation increases with the number of methylated cytosines, following the same position dependence as the single methylations. The multiple-methylation case reveals that each major groove meth- PLOS Computational Biology | www.ploscompbiol.org 3 November 2013 | Volume 9 | Issue 11 | e1003354 DNA Methylation and Nucleosome Positioning ylation destabilizes the nucleosome by around 1 kJ/mol (close to the average estimate of 2 kJ/mol obtained for from individual methylation studies), while each minor groove methylation destabilizes it by up to 5 kJ/mol (average free energy as single mutation is around 6 kJ/mol). This energetic position-dependence is the reverse of what was observed in a recent FRET/SAXS study [30]. The differences can be attributed to the use of different ionic conditions and different sequences: a modified Widom-601 sequence of 157 bp, which already contains multiple CpG steps in mixed orientations, and which could assume different positioning due to the introduction of new CpG steps and by effect of the methylation. The analysis of our trajectories reveals a larger root mean square deviation (RMSD) and fluctuation (RMSF; see Figures S2– S3 in Text S1) for the methylated nucleosomes, but failed to detect any systematic change in DNA geometry or in intermolecular DNA-histone energy related to methylation (Fig. S1B, S1C, S4–S6 in Text S1). The hydrophobic effect should favor orientation of the methyl group out from the solvent but this effect alone is not likely to justify the positional dependent stability changes in Figure 2, as the differential solvation of the methyl groups in the bound and unbound states is only in the order of a fraction of a water molecule (Figure S5 in Text S1). We find however, a reasonable correlation between methylation-induced changes in hydrogen bond and stacking interactions of the bases and the change in nucleosome stability (see Figure S6 in Text S1). This finding suggests that methylation-induced nucleosome destabilization is related to the poorer ability of methylated DNA to fit into the required conformation for DNA in a nucleosome. Changes in the elastic deformation energy between methylated and un-methylated DNA correlate with nucleosomal differential binding free energies To further analyze the idea that methylation-induced nucleosome destabilization is connected to a worse fit of methylated DNA into the required nucleosome-bound conformation, we computed the elastic energy of the nucleosomal DNA using a harmonic deformation method [36,37,44]. This method provides a rough estimate of the energy required to deform a DNA fiber to adopt the super helical conformation in the nucleosome (full details in Suppl. Information Text S1). As shown in Figure 2, there is an evident correlation between the increase that methylation produces in the elastic deformation energy (DDE def.) and the free energy variation (DDG bind.) computed from MD/TI calculations. Clearly, methylation increases the stiffness of the CpG step [31], raising the energy cost required to wrap DNA around the histone octamers. This extra energy cost will be smaller in regions of high positive roll (naked DNA MeCpG steps have a higher roll than CpG steps [31]) than in regions of high negative roll. Thus, simple elastic considerations explain why methylation is better tolerated when the DNA faces the histones through the major groove (where positive roll is required) that when it faces histones through the minor groove (where negative roll is required). Nucleosome methylation can give rise to nucleosome repositioning We have established that methylation affects the wrapping of DNA in nucleosomes, but how does this translate into chromatin structure? As noted above, accumulation of minor groove methylations strongly destabilizes the nucleosome, and could trigger nucleosome unfolding, or notable changes in positioning or phasing of DNA around the histone core. While accumulation of methylations might be well tolerated if placed in favorable positions, accumulation in unfavorable positions would destabilize the nucleosome, which might trigger changes in chromatin structure. Chromatin could in fact react in two different ways in response to significant levels of methylation in unfavorable positions: i) the DNA could either detach from the histone core, leading to nucleosome eviction or nucleosome repositioning, or ii) the DNA could rotate around the histone core, changing its phase to place MeCpG steps in favorable positions. Both effects are anticipated to alter DNA accessibility and impact gene expression regulation. The sub-microsecond time scale of our MD trajectories of methylated DNAs bound to nucleosomes is not large enough to capture these effects, but clear trends are visible in cases of multiple mutations occurring in unfavorable positions, where unmethylated and methylated DNA sequences are out of phase by around 28 degrees (Figure S7 in Text S1). Due to this repositioning, large or small, DNA could move and the nucleosome structure could assume a more compact and distorted conformation, as detected by Lee and Lee [29], or a slightly open conformation as found in Jimenez-Useche et al. [30]. Using the harmonic deformation method, we additionally predicted the change in stability induced by cytosine methylation for millions of different nucleosomal DNA sequences. Consistently with our calculations, we used two extreme scenarios to prepare our DNA sequences (see Fig. 3): i) all positions where the minor grooves contact the histone core are occupied by CpG steps, and ii) all positions where the major grooves contact the histone core are occupied by CpG steps. We then computed the elastic energy required to wrap the DNA around the histone proteins in unmethylated and methylated states, and, as expected, observed that methylation disfavors DNA wrapping (Figure 3A). We have rescaled the elastic energy differences with a factor of 0.23 to match the DDG prediction in figure 2B. In agreement with the rest of our results, our analysis confirms that the effect of methylation is position-dependent. In fact, the overall difference between the two extreme methylation scenarios (all-in-minor vs all-in-major) is larger than 60 kJ/mol, the average difference being around 15 kJ/ mol. We have also computed the elastic energy differences for a million sequences with CpG/MeCpG steps positioned at all possible intermediate locations with respect to the position (figure 3B). The large differences between the extreme cases can induce rotations of DNA around the histone core, shifting its phase to allow the placement of the methylated CpG steps facing the histones through the major groove. It is illustrative to compare the magnitude of CpG methylation penalty with sequence dependent differences. Since there are roughly 1.5e88 possible 147 base pairs long sequence combinations (i.e., (4n+4(n/2))/2, n = 147), it is unfeasible to calculate all the possible sequence effects. However, using our elastic model we can provide a range of values based on a reasonably large number of samples. If we consider all possible nucleosomal sequences in the yeast genome (around 12 Mbp), the energy difference between the best and the worst sequence that could form a nucleosome is 0.7 kj/mol per base (a minimum of 1 kJ/mol and maximum of around 1.7 kJ/mol per base, the first best and the last worst sequences are displayed in Table S3 in Text S1). We repeated the same calculation for one million random sequences and we obtained equivalent results. Placing one CpG step every helical turn gives an average energetic difference between minor groove and major groove methylation of 15 kJ/ mol, which translates into ,0.5 kJ/mol per methyl group, 2 kJ/ mol per base for the largest effects. Considering that not all nucleosome base pair steps are likely to be CpG steps, we can conclude that the balance between the destabilization due to CpG methylation and sequence repositioning will depend on the PLOS Computational Biology | www.ploscompbiol.org 4 November 2013 | Volume 9 | Issue 11 | e1003354 DNA Methylation and Nucleosome Positioning Figure 3. Methylated and non-methylated DNA elastic deformation energies. (A) Distribution of deformation energies for 147 bplong random DNA sequences with CpG steps positioned every 10 base steps (one helical turn) in minor (red and dark red) and major (light and dark blue) grooves respectively. The energy values were rescaled by the slope of a best-fit straight line of figure 2, which is 0.23, to por la lectura a través de la lectura de la prensa. La educación en los medios las fuerzas dispersas en función de los soportes mediáticos y orientarse más hacia la educación en medios que al dominio adquiere pleno derecho y entidad en la sección sexta titulada «competencias sociales y cívi- técnico de los aparatos. cas» que indica que «los alum- nos deberán ser capaces de juz- gar y tendrán espíritu crítico, lo que supone ser educados en los las programaciones oficiales, ya que, a lo largo de un medios y tener conciencia de su lugar y de su influencia estudio de los textos, los documentalistas del CLEMI en la sociedad». han podido señalar más de una centena de referencias a la educación de los medios en el seno de disciplinas 4. Un entorno positivo como el francés, la historia, la geografía, las lenguas, Si nos atenemos a las cifras, el panorama de la las artes plásticas : trabajos sobre las portadas de educación en medios es muy positivo. Una gran ope- prensa, reflexiones sobre temas mediáticos, análisis de ración de visibilidad como la «Semana de la prensa y publicidad, análisis de imágenes desde todos los ángu- de los medios en la escuela», coordinada por el CLE- los, reflexión sobre las noticias en los países europeos, MI, confirma año tras año, después de 17 convocato- información y opinión rias, el atractivo que ejerce sobre los profesores y los Esta presencia se constata desde la escuela mater- alumnos. Concebida como una gran operación de nal (2 a 6 años) donde, por ejemplo, se le pregunta a complementariedad entre la escuela y los profesiona- los niños más pequeños si saben diferenciar entre un les de los medios, alrededor del aprendizaje ciudada- periódico, un libro, un catálogo, a través de activida- no de la comunicación mediática, este evento moviliza des sensoriales, si saben para qué sirve un cartel, un durante toda una semana un porcentaje elevado de periódico, un cuaderno, un ordenador si son capa- centros escolares que representan un potencial de 4,3 ces de reconocer y distinguir imágenes de origen y de millones de alumnos (cifras de 2006). Basada en el naturaleza distintas. Podríamos continuar con más voluntariado, la semana permite desarrollar activida- ejemplos en todos los niveles de enseñanza y práctica- des más o menos ambiciosas centradas en la introduc- Páginas 43-48 ción de los medios en la vida de la escuela a través de la instalación de kioscos, organización de debates con profesionales y la confección por parte de los alumnos de documentos difundidos en los medios profesionales. Es la ocasión de dar un empujón a la educación en medios y de disfrutarlos. Los medios –un millar en 2006– se asocian de maneras diversas ofreciendo ejemplares de periódicos, acceso a noticias o a imágenes, proponiendo encuentros, permitiendo intervenir a los jóvenes en sus ondas o en sus columnas Esta operación da luz al trabajo de la educación en medios y moviliza a los diferentes participantes en el proyecto. 5. La formación de los docentes La formación es uno de los pilares principales de la educación en los medios. Su función es indispensable ya que no se trata de una disciplina, sino de una enseñanza que se hace sobre la base del voluntariado y del compromiso personal. Se trata de convencer, de mostrar, de interactuar. En primer lugar es necesario incluirla en la formación continua de los docentes, cuyo volumen se ha incrementado desde 1981 con la aparición de una verdadera política de formación continua de personal. Es difícil dar una imagen completa del volumen y del público, pero si nos atenemos a las cifras del CLEMI, hay más de 24.000 profesores que han asistido y se han involucrado durante 2004-05. 5.1. La formación continua En la mayoría de los casos, los profesores reciben su formación en contextos cercanos a su centro de trabajo, o incluso en este mismo. Después de una política centrada en la oferta que hacían los formadores, se valora más positivamente la demanda por parte del profesorado, ya que sólo así será verdaderamente fructífera. Los cursos de formación se repartieron en varias categorías: desde los formatos más tradicionales (cursos, debates, animaciones), hasta actividades de asesoramiento y de acompañamiento, y por supuesto los coloquios que permiten un trabajo en profundidad ya que van acompañados de expertos investigadores y profesionales. Citemos, por ejemplo en 2005, los coloquios del CLEMI-Toulouse sobre el cine documental o el del CLEMI-Dijon sobre «Políticos y medios: ¿connivencia?». Estos coloquios, que forman parte de un trabajo pedagógico regular, reagrupan a los diferentes participantes regionales y nacionales alrededor de grandes temas de la educación en medios y permiten generar nuevos conocimientos de aproximación y una profundización. Páginas 43-48 Hay otro tipo de formación original que se viene desarrollando desde hace menos tiempo, a través de cursos profesionales, como por ejemplo, en el Festival Internacional de Foto-periodismo «Visa para la imagen», en Perpignan. La formación se consolida en el curso, da acceso a las exposiciones, a las conferencias de profesionales y a los grandes debates, pero añade además propuestas pedagógicas y reflexiones didácticas destinadas a los docentes. Estas nuevas modalidades de formación son también consecuencia del agotamiento de la formación tradicional en las regiones. Los contenidos más frecuentes en formación continua conciernen tanto a los temas más clásicos como a los cambios que se están llevando a cabo en las prácticas mediáticas. Así encontramos distintas tendencias para 2004-05: La imagen desde el ángulo de la producción de imágenes animadas, el análisis de la imagen de la información o las imágenes del J.T. La prensa escrita y el periódico escolar. Internet y la información en línea. Medios y educación de los medios. 5.2 La formación inicial La formación inicial está aun en un grado muy ini- cial. El hecho de que la educación en medios no sea una disciplina impide su presencia en los IUFM (Institutos Universitarios de Formación de Maestros) que dan una prioridad absoluta a la didáctica de las disciplinas. En 2003, alrededor de 1.400 cursillistas sobre un total de 30.000 participaron en un momento u otro de un módulo de educación en medios. Estos módulos se ofrecen en función del interés que ese formador encuentra puntualmente y forman parte a menudo de varias disciplinas: documentación, letras, historia-geografía Estamos aún lejos de una política concertada en este dominio. La optativa «Cine-audiovisual» ha entrado desde hace muy poco tiempo en algunos IUFM destinada a obtener un certificado de enseñanza de la opción audiovisual y cine. Internet tiene cabida también en los cursos de formación inicial, recientemente con la aparición de un certificado informático y de Internet para los docentes, dirigido más a constatar competencias personales que a valorar una aptitud para enseñarlos. 6. ¿Y el futuro? El problema del futuro se plantea una vez más por la irrupción de nuevas técnicas y nuevos soportes. La difusión acelerada de lo digital replantea hoy muchas cuestiones relativas a prácticas mediáticas. Muchos Comunicar, 28, 2007 47 Comunicar, 28, 2007 Enrique Martínez-Salanova '2007 para Comunicar 48 trabajos que llevan el rótulo de la educación en medios solicitan una revisión ya que los conceptos cambian. La metodología elaborada en el marco de la educación en medios parece incluso permitir la inclinación de la sociedad de la información hacia una sociedad del conocimiento, como defiende la UNESCO. En Francia, se necesitaría unir las fuerzas dispersas en función de los soportes mediáticos y orientarse más hacia la educación en medios que al dominio técnico de los aparatos. Los avances recientes en el reconocimiento de estos contenidos y las competencias que supondrían podrían permitirlo. Referencias CLEMI/ACADEMIE DE BORDEAUX (Ed.) (2003): Parcours médias au collège: approches disciplinaires et transdisciplinaires. Aquitaine, Sceren-CRDP. GONNET, J. (2001): Education aux médias. Les controverses fécondes. Paris, Hachette Education/CNDP. SAVINO, J.; MARMIESSE, C. et BENSA, F. (2005): L’éducation aux médias de la maternelle au lycée. Direction de l’Enseignement Scolaire. Paris, Ministère de l’Education Nationale, Sceren/CNDP, Témoigner. BEVORT, E. et FREMONT, P. (2001): Médias, violence et education. Paris, CNDP, Actes et rapports pour l’éducation. – www.clemi.org: fiches pédagogiques, rapports et liens avec les pages régionales/académiques. – www.ac-nancy-metz.fr/cinemav/quai.html: Le site «Quai des images» est dédié à l’enseignement du cinéma et de l’audiovisuel. – www.france5.fr/education: la rubrique «Côté profs» a une entrée «education aux médias». – www.educaunet.org: Programme européen d’éducation aux risques liés à Internet. dResedfeleexliobnuetsacón Páginas 43-48
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