**4. Effect of different protein sources on animal performance**

Several researches have been carried out in order to compare the nutritional characteristics of soybean solvent extract and legume grains, as faba bean, peas and lupine, for ruminant feeding.

Di Francia et al. (2007) evaluated the effect of partial replacement of soybean cake with extruded peas in the diet of lactating buffalo cows on milk yield and quality over the first 100 days of lactation. Their results showed that peas could represent an attractive GMO free

Protein Sources in Ruminant Nutrition 205

No significant differences between the groups were found for carcass measurements. In each case the carcass measurements of this trial ranged into the interval indicated by Keane

Protein source influenced neither body and carcasses conformations nor dressing out with the exception of the incidence of long bones showed a significant difference (6.2 vs 6.7 for

The first quality meat cuts were acceptable in both groups (58.1 and 57.8%, for faba and soybean, respectively). Concerning the comparison between the two protein sources, only the incidence of long bones showed a significant difference (6.2 vs 6.7 for faba and soybean, respectively; P<0.05). It is important to underline that the sample cut measurements were contradictory and conflicted with the data obtained from total carcass dissection. The results of the sample cut dissection indicated a significant (P<0.05) difference between groups faba and soybean in meat incidence (69.4 vs 66.9, for faba and soybean, respectively); while no differences were found between groups at carcass dissection. Moreover, sample cut of soybean group showed in the meantime the smallest meat incidence and the highest LT area

The animals fed faba bean showed significantly higher water losses, measured with the compression method (WHC 7.6 vs. 5.7% for faba and soybean group, respectively; P<0.01). Our grilling loss data (31.7 vs. 28.3 % for faba and soybean group, respectively; P>0.01) were higher than those reported by Sami *et al.* (2004) in Simmental young bulls but they were in agreement with those reported by Pen *et al.* (2005) cooking ST samples of Holstein steers in an oven, on the contrary our drip loss data resulted higher than that reported by these

The chemical composition of LT was not statistically different between groups. Meat from both groups showed a very low fat content (<3%) and higher protein concentrations than the Holstein steers (Pen *et al.*, 2005), confirming the high quality of the Marchigiana meat. Hydroxyproline (60.0 vs. 62.6 mg 100g-1 of meat, in group faba and soybean, respectively) contents were not influenced by protein sources. Regarding the differences registered for this parameter among the texted muscles (LT: *Longissimus thoracis*; ST: *Semitendinosus*; IP: *Iliopsoas* plus *Psoas minor*) the IP samples, which correspond to the tenderloin, showed in all the groups significantly (P<0.01) lower hydroxyproline concentrations than the other two muscles; also between the LT and ST muscles the differences were statistically significant

Cholesterol content (56.3 vs.55.1 mg 100g-1 of meat, in group faba and soybean, respectively) was not influenced by protein sources according to the observations of Cutrignelli (2000) on

Considering the differences among the muscles, cholesterol values were significantly (P<0.05) lower for IP. Cifuni *et al.* (2004) found no differences in cholesterol contents among muscles, while Rusman *et al*. (2003) found significant differences. This contradiction is probably due to the different muscles analysed in each experiment. As theorised by Wheeler *et al.* (1987) the cholesterol content may be affected by the different physiological function of the muscles. In both groups, and especially for LT and ST muscles, the cholesterol contents were slightly higher than the value (less than 50 mg100g-1 of muscle) indicated by the Protected Geographical Indication (PGI) of the "Vitellone Bianco dell'Appennino Centrale" (Council Regulation EEC No 2081/92; Floroni, 2002). Nevertheless, our results are very close

Podolian young bulls and by Poli *et al.* (1996) on Chianina young bulls.

No differences were found in dressing out, organs and tare incidence on net weight.

(2003) for European/North American breeds.

(88.4 vs. 84 for soybean and faba group, respectively).

faba and soybean, respectively; P<0.05).

(P<0.05) being lower for the former.

authors.

protein feed when approaching the problem of the choice of a protein source alternative to soybean in diet formulation for buffalo cows raised in organic farms.

On the other hand Morbidini et al (2005) investigating on the effect of two different fattening diets with different protein sources - soybean meal and flaked faba bean - on slaughtering performance and carcass quality in light Apennine and Italian Merino lambs, observed that the use of faba beans lightly depressed growth performance (Morbidini et al., 2004) and slaughtering weight, even if did not affect the carcass quality.

In order to make a contribution on this issue, our research group conducted a trial on the effect of protein source on growth performance and meat quality of Marchigiana young bulls (Cutrignelli et al 2008 a, b).

The trial was carried out on a farm situated at 700 m a.s.l. in Campania Region (Southern Italy), where 12 weaned young bulls (129 d of age) were equally divided into two groups. Each animal was placed in individual box up to the slaughtering weight (620 kg).

The groups were fed diets with the same protein and energy concentrations and the same forage/concentrate ratios (F/C), but differing in protein source: faba bean (*Vicia faba minor* L.) vs soybean meal (*Soja hispida*).

All the animals were regularly weighed until the body weight (BW) of 620 kg fixed in advance as slaughter weight, was reached. All animals were slaughtered in an authorized slaughterhouse according to EU legislation (EU Regulation EC No 882/2004).

Live animals and carcasses were weighed and measured according to ASPA (1991). After 9 days of refrigeration at 4 ± 1 °C, dissection of the carcasses was carried out.

Samples of *Longissimus thoracis* (LT), *Semitendinosus* (ST), *Iliopsoas* plus *Psoas minor* (IP) muscles, perirenal (PF) and subcutaneous (SF) adipose tissues were collected and rapidly transported, upon refrigeration temperature, to the laboratories for the chemical analysis in order to evaluate the rheological (water holding capacity) and nutritional (chemical composition fatty acid profile, cholesterol and hydrossiproline contents) characteristics of meat.

The protein source did not affect any *infra vitam* parameters except the body weight (BW) at 180 d of age ( 173 vs. 186 kg, for group FB and SB, respectively; P<0.01).

The difference was probably due to the higher non-protein nitrogen (NPN) concentration of the faba bean than the soybean meal (about 12 vs 1.3% of crude protein, respectively). Indeed, in the months immediately following the weaning it should be preferable to administer diets with higher rumen undegradable protein content because at this age the rumen is not yet perfectly functional and microbial protein synthesis is less efficient. Furthermore, for the same reason, the animals in this period are probably unable to neutralize possible anti-nutritional factors of faba beans.

As respects the influence of the replacement of soybean meal solvent extract with legumes seeds, the literature results are contrasting. Moss et al. (1997) found no significant effects on weight gain and feed intake when soybean meal was replaced on an iso-protein basis by lupin seeds in diets for growing bulls (BW from 182 to 243 kg); similar results are reported by Kwak and Kim (2001) on Korean native bulls (BW from 247 to 427 kg) utilising two different concentrations (15 and 30%) of flaked lupin. Instead, according to our results, Murphy and McNiven (1994) found significantly higher weight gain in growing steers (BW from 235.2 to 343.7 kg) fed soybean meal vs raw or roasted lupin although the differences were not significant in the finishing phase (final BW 503.4 kg).

protein feed when approaching the problem of the choice of a protein source alternative to

On the other hand Morbidini et al (2005) investigating on the effect of two different fattening diets with different protein sources - soybean meal and flaked faba bean - on slaughtering performance and carcass quality in light Apennine and Italian Merino lambs, observed that the use of faba beans lightly depressed growth performance (Morbidini et al., 2004) and

In order to make a contribution on this issue, our research group conducted a trial on the effect of protein source on growth performance and meat quality of Marchigiana young

The trial was carried out on a farm situated at 700 m a.s.l. in Campania Region (Southern Italy), where 12 weaned young bulls (129 d of age) were equally divided into two groups.

The groups were fed diets with the same protein and energy concentrations and the same forage/concentrate ratios (F/C), but differing in protein source: faba bean (*Vicia faba minor*

All the animals were regularly weighed until the body weight (BW) of 620 kg fixed in advance as slaughter weight, was reached. All animals were slaughtered in an authorized

Live animals and carcasses were weighed and measured according to ASPA (1991). After 9

Samples of *Longissimus thoracis* (LT), *Semitendinosus* (ST), *Iliopsoas* plus *Psoas minor* (IP) muscles, perirenal (PF) and subcutaneous (SF) adipose tissues were collected and rapidly transported, upon refrigeration temperature, to the laboratories for the chemical analysis in order to evaluate the rheological (water holding capacity) and nutritional (chemical composition fatty acid profile, cholesterol and hydrossiproline contents) characteristics of

The protein source did not affect any *infra vitam* parameters except the body weight (BW) at

The difference was probably due to the higher non-protein nitrogen (NPN) concentration of the faba bean than the soybean meal (about 12 vs 1.3% of crude protein, respectively). Indeed, in the months immediately following the weaning it should be preferable to administer diets with higher rumen undegradable protein content because at this age the rumen is not yet perfectly functional and microbial protein synthesis is less efficient. Furthermore, for the same reason, the animals in this period are probably unable to

As respects the influence of the replacement of soybean meal solvent extract with legumes seeds, the literature results are contrasting. Moss et al. (1997) found no significant effects on weight gain and feed intake when soybean meal was replaced on an iso-protein basis by lupin seeds in diets for growing bulls (BW from 182 to 243 kg); similar results are reported by Kwak and Kim (2001) on Korean native bulls (BW from 247 to 427 kg) utilising two different concentrations (15 and 30%) of flaked lupin. Instead, according to our results, Murphy and McNiven (1994) found significantly higher weight gain in growing steers (BW from 235.2 to 343.7 kg) fed soybean meal vs raw or roasted lupin although the differences

Each animal was placed in individual box up to the slaughtering weight (620 kg).

slaughterhouse according to EU legislation (EU Regulation EC No 882/2004).

days of refrigeration at 4 ± 1 °C, dissection of the carcasses was carried out.

180 d of age ( 173 vs. 186 kg, for group FB and SB, respectively; P<0.01).

neutralize possible anti-nutritional factors of faba beans.

were not significant in the finishing phase (final BW 503.4 kg).

soybean in diet formulation for buffalo cows raised in organic farms.

slaughtering weight, even if did not affect the carcass quality.

bulls (Cutrignelli et al 2008 a, b).

L.) vs soybean meal (*Soja hispida*).

meat.

No significant differences between the groups were found for carcass measurements. In each case the carcass measurements of this trial ranged into the interval indicated by Keane (2003) for European/North American breeds.

No differences were found in dressing out, organs and tare incidence on net weight.

Protein source influenced neither body and carcasses conformations nor dressing out with the exception of the incidence of long bones showed a significant difference (6.2 vs 6.7 for faba and soybean, respectively; P<0.05).

The first quality meat cuts were acceptable in both groups (58.1 and 57.8%, for faba and soybean, respectively). Concerning the comparison between the two protein sources, only the incidence of long bones showed a significant difference (6.2 vs 6.7 for faba and soybean, respectively; P<0.05). It is important to underline that the sample cut measurements were contradictory and conflicted with the data obtained from total carcass dissection. The results of the sample cut dissection indicated a significant (P<0.05) difference between groups faba and soybean in meat incidence (69.4 vs 66.9, for faba and soybean, respectively); while no differences were found between groups at carcass dissection. Moreover, sample cut of soybean group showed in the meantime the smallest meat incidence and the highest LT area (88.4 vs. 84 for soybean and faba group, respectively).

The animals fed faba bean showed significantly higher water losses, measured with the compression method (WHC 7.6 vs. 5.7% for faba and soybean group, respectively; P<0.01).

Our grilling loss data (31.7 vs. 28.3 % for faba and soybean group, respectively; P>0.01) were higher than those reported by Sami *et al.* (2004) in Simmental young bulls but they were in agreement with those reported by Pen *et al.* (2005) cooking ST samples of Holstein steers in an oven, on the contrary our drip loss data resulted higher than that reported by these authors.

The chemical composition of LT was not statistically different between groups. Meat from both groups showed a very low fat content (<3%) and higher protein concentrations than the Holstein steers (Pen *et al.*, 2005), confirming the high quality of the Marchigiana meat.

Hydroxyproline (60.0 vs. 62.6 mg 100g-1 of meat, in group faba and soybean, respectively) contents were not influenced by protein sources. Regarding the differences registered for this parameter among the texted muscles (LT: *Longissimus thoracis*; ST: *Semitendinosus*; IP: *Iliopsoas* plus *Psoas minor*) the IP samples, which correspond to the tenderloin, showed in all the groups significantly (P<0.01) lower hydroxyproline concentrations than the other two muscles; also between the LT and ST muscles the differences were statistically significant (P<0.05) being lower for the former.

Cholesterol content (56.3 vs.55.1 mg 100g-1 of meat, in group faba and soybean, respectively) was not influenced by protein sources according to the observations of Cutrignelli (2000) on Podolian young bulls and by Poli *et al.* (1996) on Chianina young bulls.

Considering the differences among the muscles, cholesterol values were significantly (P<0.05) lower for IP. Cifuni *et al.* (2004) found no differences in cholesterol contents among muscles, while Rusman *et al*. (2003) found significant differences. This contradiction is probably due to the different muscles analysed in each experiment. As theorised by Wheeler *et al.* (1987) the cholesterol content may be affected by the different physiological function of the muscles. In both groups, and especially for LT and ST muscles, the cholesterol contents were slightly higher than the value (less than 50 mg100g-1 of muscle) indicated by the Protected Geographical Indication (PGI) of the "Vitellone Bianco dell'Appennino Centrale" (Council Regulation EEC No 2081/92; Floroni, 2002). Nevertheless, our results are very close

Protein Sources in Ruminant Nutrition 207

taste panel evaluation (Westerling and Hedrick, 1979) and food with high UFA, especially PUFA, is good for human health (Rusman *et al.*, 2003). The ω-6/ω-3 ratio was higher than the value (less than 3) reported by Scollan *et al.* (2006) but lower than that registered by

It has to be underlined that the fatty acid profile o the food arouse high interest in human medicine due to their influence on the functionality of the cardio-circulatory apparatus. A number of epidemiological researches put in evidence that diets with high content of saturated fatty acids (SFA) were associated with high levels of serum cholesterol (especially of low density lipoprotein, LDL) which appear important in atheroma. Successively,

2. short-chain SFA (C 10 and below) likewise do not raise blood cholesterol, so the putative atherogenic SFA are C12:0 (lauric), C14:0 (myristic) and C16:0 (palmitic). Myristic acid is the most atherogenic, with about four times the cholestrol-raising

PUFA are considered protective factors: ω-6 fatty acids show mainly anti-atherogenic activity while ω-3 fatty acids have anti-thrombogenic activity. More recently, high prominence is attributed to the role developed by the MUFA, and particularly by the oleic acid that, reducing the oxidation of the cholesterol LDL, may slow the progression of

As was pointed out above, the P/S (poliunsaturated/saturated) ratio is not suitable measure of the atherogenicity or thrombogenicity of a diet or foods. Currently they are expressed as

*Index of atherogenicity:* C12:0 + (4 x C14:0) + C16:0/ ω-3 + ω-6 + MUFA

*Index of thrombogenicity:* C14:0 + C16:0 +C18:0/(0,5 x C18:1) + (0,5 other MUFA) + 0,5(ω-6) + 3(ω-3) + (ω-3/ ω-6). The AI of the meat in this trial was particularly interesting, rather lower than the data reported by Ulbricht and Southgate (1991) for raw minced beef and than those reported by Badiani *et al.* (2002) for cooked beef (0.72 and 0.77, respectively); our data were similar to

FB SB Significance

SFA 365.1 39.1 330.6 26.9 Ns MUFA 244.3 39.5 271.7 29.4 Ns PUFA 186.6 20.5 201.9 15.7 Ns -6 174.2 19.9 188.3 12.9 Ns -3 12.39 1.5 13.57 0.8 Ns AI 0.54 0.04 0.49 0.07 Ns TI 1.46 0.12 1.20 0.09 Ns

*FB: faba bean; SB: soybean meal solvent extract;AI: atherogenic index; TI thrombogenic index.* 

Table 7. Fatty acid profile of Longissimus thoracis muscle (mg 100g-1 of edible part).

Warren *et al.* (2003) for steers fed corn silage and concentrates (8.9).

1. diets high in C18:0, stearic acid, do not raise serum cholesterol;

those of Poli *et al.* (1996) on Chianina young bulls (AI: 0.58).

Ulbricht and Southgate (1991) reported that:

potential of palmitic acid.

atherosclerosis.

*ns: not significant.* 

follows:

to those reported for Italian meat breeds (Poli *et al.* 1996; Cifuni *et al.,* 2004) and lower than those from other breeds (Migdal *et al.*, 2004).

Regarding the fatty acids profile in both groups and in each analysed tissues (intramuscular, perirenal and subcutaneous adipose tissues) palmitic (C16:0), stearic (C18:0) and oleic (C18:1) acids were the most widely represented fatty acids. In particular, in intramuscular fat, the sum of oleic, stearic and palmitic acids represents over 50% of total fatty acids, according to the observations of Cifuni *et al.* (2004) and Migdal *et al.* (2004).

Comparing the data of groups faba and soybean, the only significant (P<0.01) difference was for stearic acid being higher for bulls fed faba bean than for those fed soybean meal solvent extract. However this result did not significantly affect the SFA concentration, or AI and TI indexes (table 7).

Protein source did not affected the fatty acids composition of the analysed adipose tissues. This is probably due to the very low concentration of phospholipids in subcutaneous and perirenal fat tissue.

**C**omparing the fatty acid composition of the three adipose tissues the following differences were noted:


The LT fatty acid profile was similar to those reported by Raes *et al.* (2003) for *Longissimus lumborum* of Belgian Blue and Limousin beef (SFA: 338 and 506 mg 100g-1 edible portion; MUFA: 323 and 554 mg 100g-1 edible portion; PUFA: 195 and 195 mg 100g-1 edible portion; in Belgian Blue and Limousin bulls, respectively) and different from values found in Irish and Argentine beef. The latter showed significantly higher total intramuscular fatty acid content compared to the former, probably due to genetic selection.

This observation confirms that of Carnovale and Nicoli (2000) who concluded that Italian meat showed a favourable intramuscular fatty acid composition with high PUFA content. Muscle with a high percentage of unsaturated fatty acids (UFA) generally scored higher in

to those reported for Italian meat breeds (Poli *et al.* 1996; Cifuni *et al.,* 2004) and lower than

Regarding the fatty acids profile in both groups and in each analysed tissues (intramuscular, perirenal and subcutaneous adipose tissues) palmitic (C16:0), stearic (C18:0) and oleic (C18:1) acids were the most widely represented fatty acids. In particular, in intramuscular fat, the sum of oleic, stearic and palmitic acids represents over 50% of total fatty acids,

Comparing the data of groups faba and soybean, the only significant (P<0.01) difference was for stearic acid being higher for bulls fed faba bean than for those fed soybean meal solvent extract. However this result did not significantly affect the SFA concentration, or AI and TI

Protein source did not affected the fatty acids composition of the analysed adipose tissues. This is probably due to the very low concentration of phospholipids in subcutaneous and

**C**omparing the fatty acid composition of the three adipose tissues the following differences





The LT fatty acid profile was similar to those reported by Raes *et al.* (2003) for *Longissimus lumborum* of Belgian Blue and Limousin beef (SFA: 338 and 506 mg 100g-1 edible portion; MUFA: 323 and 554 mg 100g-1 edible portion; PUFA: 195 and 195 mg 100g-1 edible portion; in Belgian Blue and Limousin bulls, respectively) and different from values found in Irish and Argentine beef. The latter showed significantly higher total intramuscular fatty acid

This observation confirms that of Carnovale and Nicoli (2000) who concluded that Italian meat showed a favourable intramuscular fatty acid composition with high PUFA content. Muscle with a high percentage of unsaturated fatty acids (UFA) generally scored higher in

influenced by several factors such as adipocite size, nutrient supply, etc.;

according to the observations of Cifuni *et al.* (2004) and Migdal *et al.* (2004).

and an increased PUFA content (Scollan *et al.*, 2006);

tissues as well as to the high PUFA concentration of LT.

content compared to the former, probably due to genetic selection.

those from other breeds (Migdal *et al.*, 2004).

indexes (table 7).

perirenal fat tissue.

were noted:

tissues;

taste panel evaluation (Westerling and Hedrick, 1979) and food with high UFA, especially PUFA, is good for human health (Rusman *et al.*, 2003). The ω-6/ω-3 ratio was higher than the value (less than 3) reported by Scollan *et al.* (2006) but lower than that registered by Warren *et al.* (2003) for steers fed corn silage and concentrates (8.9).

It has to be underlined that the fatty acid profile o the food arouse high interest in human medicine due to their influence on the functionality of the cardio-circulatory apparatus. A number of epidemiological researches put in evidence that diets with high content of saturated fatty acids (SFA) were associated with high levels of serum cholesterol (especially of low density lipoprotein, LDL) which appear important in atheroma. Successively, Ulbricht and Southgate (1991) reported that:


PUFA are considered protective factors: ω-6 fatty acids show mainly anti-atherogenic activity while ω-3 fatty acids have anti-thrombogenic activity. More recently, high prominence is attributed to the role developed by the MUFA, and particularly by the oleic acid that, reducing the oxidation of the cholesterol LDL, may slow the progression of atherosclerosis.

As was pointed out above, the P/S (poliunsaturated/saturated) ratio is not suitable measure of the atherogenicity or thrombogenicity of a diet or foods. Currently they are expressed as follows:

$$\text{Index of otherwise:}\\\text{c.C12:}\\0 + (4 \ge \text{C14:} 0) + \text{C16:} 0\\\text{/ } \text{a-S} + \text{a-6} + \text{MUFA}$$

*Index of thrombogenicity:* C14:0 + C16:0 +C18:0/(0,5 x C18:1) + (0,5 other MUFA) + 0,5(ω-6) + 3(ω-3) + (ω-3/ ω-6).

The AI of the meat in this trial was particularly interesting, rather lower than the data reported by Ulbricht and Southgate (1991) for raw minced beef and than those reported by Badiani *et al.* (2002) for cooked beef (0.72 and 0.77, respectively); our data were similar to those of Poli *et al.* (1996) on Chianina young bulls (AI: 0.58).


*FB: faba bean; SB: soybean meal solvent extract;AI: atherogenic index; TI thrombogenic index. ns: not significant.* 

Table 7. Fatty acid profile of Longissimus thoracis muscle (mg 100g-1 of edible part).

Protein Sources in Ruminant Nutrition 209

In addition, our *in vivo* studies concerning the *infra vitam* and *post mortem* performances of




From these results, it can be concluded that the use of grain legumes as a protein source in ruminant diets could be used as alternative to soybean meal. However, mainly in the intensive livestock system the soybean meal solvent extract represents the protein source par excellence for the high protein content (in particular undegradable fraction), the absence of anti-nutritional factors and the extremely favourable biological value of its proteins. Not insignificant, then is the economic assessment, soybean is, especially in the areas where the ruminants breeding has been particularly developed, the protein source with the

By contrast, it has to be underlined that biotech herbicide tolerant soybean continued to be the principal biotech crop in 2010, occupying 73.3 million hectares or 50% of global biotech area. Farm animals are currently fed soybean and soybean meal developed from genetic transformation. Europe is strongly dependent upon the American continent for its protein

Thus, the possible risk connected to genetically modified organisms use in animal breeding has led to the reconsideration of animal production processes with special reference to the use of alternative protein sources (e.g. faba beans, dried peas, lupine seeds, chickpeas) able to replace soybean. These legumes have agronomic importance because they improve soil fertility and reduce nitrogenous dressing, with positive effects on environmental pollution. Moreover, they need a limited initial investment for their modest requirements of chemical

A.S.P.A. (1991). Metodologie relative alla macellazione degli animali di interesse zootecnico ed alla valutazione e dissezione della loro carcasse. Ed. ISMEA, Roma. Akpinar, N., Akpinar, M.A. & Türkoglu, S. (2001). Total lipid content and fatty acid composition of the seeds of some Vicia L. species. *Food Chem.*, 74, pp. 449–453. Arieli, A., Bruckental, I., Kedar. & I., Sklan, D. (1995). *In sacco* disappearance Of starch nitrogen and fat in processed grains. *Anim. Feed sci. Techn*., 51, pp. 287-295. Bach Knudsen, K.E. (1997). Carbohydrate and lignin contents of plant materials used in

Badgley, C., Moghtader, J., Quintero, E., Zakem, E., Chappell, M.J., Avilés-Vázquez, K.,

Samulon, A. & Perfecto, I., (2007). Organic agriculture and the global food supply.

animal feeding. *Anim. Feed Sci. Technol.*, 67, pp. 319–338.

*Renew. Agric. Food Sys.,* 22, pp. 86–108.

young bulls fed either faba bean or soybean showed:

lower for the group receiving faba bean.

quality/price ratio more favourable.

requirements amounting up to 90 to 95%.

and energetic inputs and their short culture cycle.

**6. References** 

biological efficiency of growth) and feed conversion indexes;

thrombogenic indexes, nor the cholesterol content were influenced;

However, the index of thrombogenicity in this trial was higher than the findings of the above-cited authors (1.27 and 1.30 for Ulbricht and Southgate, 1991 and Poli *et al.*, 1996, respectively); only the TI (1.77) reported by Badiani *et al.* (2002) was similar to our data.

These results show that the faba bean could be used as an alternative protein source to soybean meal solvent extract as it did not affect the growth rate (body weight, daily weight gain and biological efficiency of growth) or the feed conversion indexes during the whole experimental period, and offers decided agronomical, economical and healthy advantages.

Nevertheless, in the first period after weaning the faba bean reduced the growth rate, probably due to the higher concentrations of NPN and anti-nutritional factors. It might be useful in this period to use this protein source associated with other richer in rumen undegradable.

Our results contribute to show that both protein sources (soybean meal and faba bean) could be utilised in the diet for young Marchigiana bulls ensuring the high quality of the meat obtained by this breed.

Although the meat of group fed faba bean had significantly higher concentrations of stearic acid compared to the level found in soybean group, neither the atherogenic and thrombogenic indexes, nor the cholesterol content were influenced.

As regards the effect of protein source on organolepitc characteristics, our results on hydroxyproline content and water holding capacity were conflicting. While the meat of the group fed soybean meal solvent extract showed a potential low tenderness (higher level of hydroxiproline) the water holding capacity measured by compression was lower for the group receiving faba bean.

From our results it is also possible to formulate a favourable assessment of the nutritional characteristics of the of meat Marchigiana young bulls. Indeed, the cholesterol values were very close to those indicated by the PGI of the "Vitellone Bianco dell'Appennino Centrale" and lower than those found in other breeds. Moreover, the fatty acids profile of LT confirms that the meat of the Italian breed specialised in meat production has higher unsaturated fatty acids concentration and lower saturated fatty acids levels, which in turn ensures medium-low atherogenic and thrombogenic indexes.
