Effect of Crude Palm Oil (Cpo) Protected by Formaldehyde on Physical and Chemical Quality of Lamb

This study was conducted to determine the effect of crude palm oil (CPO) protected byformaldehyde on chemical and physical quality of lamb. The research design applied was completelyrandomized design with 3 treatments and 5 replications Fifteen local male sheeps aged 9-12 monthsweighing 14-17 kg were divided into 3 groups for different ration treatments. The first group receivedonly basal ration (R0), the 2nd group received basal ration and 3% of CPO (R1), while the 3rd groupreceived basal ration and 3% of CPO protected by 2% of formaldehyde (R2). The data were analyzed byanalysis of variance. The differences among treatments were tested by Duncan's New Multiple RangeTest. The results showed that the addition of CPO protected by formaldehyde (R2) in the sheep dietincreased lamb protein and fat content (P<0.05), produced tenderer lamb (P<0.01) with lower cookingloss (P<0.01). The diet with CPO protected by formaldehyde can improve the chemical and physicalquality of meat sheeps.


INTRODUCTION
Fatty acids in ruminant meat were dominated by saturated fatty acids. This is becaused unsaturated fatty acids (linoleic-C18:2 and linolenic-C18:3) in the diet are hydrogenated by rumen microbes become saturated fatty acids, especially stearic acid (C18:0) (Jenkins et al., 2008;Wang et al., 2010), so that only about 10% joined the lipid tissues (Wood et al., 2008), whereas 90% were hydrogenated into saturated fatty acids. Based on the final product, hydrogenation of unsaturated fatty acids are completely done by two groups of bacteria, namely (1) group A, which hydrogenate C18:2 and C18:3 with the final product of trans-C18: 1; and (2) group B, which hydrogenate trans-C18:1 with the final product of C18:0 (Bauman et al., 2003).
In addition, unsaturated fatty acids in ruminants diet would disturb rumen fermentation and reduce the utilization of fiber (Hristov et al., 2009;Vafa et al., 2009). This is caused fat can wrap feed particles and close access of microbial cell membrane to contact feed, thereby disrupting the enzymes production to degrade feed, so that decrease feed digestibility and meat quality.
The in vitro study has been done using crude palm oil (CPO) as a source of unsaturated fatty acids as much as 0%; 1.5%; 3%; 4.5%; 5% and 6% of the dry matter that is mixed by expired milk powder (1:2) and protected with technical formaldehyde as 0%; 1%; 2% and 3% of the mixture. The result showed that CPO as much as 3% of the dry matter protected with 2% of formaldehyde can protect unsaturated fatty acids from rumen microbial hydrogenation and no negative effect on fermentation parameters and rumen microbial activity (Tiven et al., 2011). This is in line with Kitessa et al. (2001) andde Veth et al. (2005) research, that protection of fat with formaldehyde can reduce the hydrogenation of unsaturated fatty acids in feed by rumen microbial.
Results of in vitro studies need to be applied in vivo to determine the effect of CPO protected with formaldehyde in the diet on the chemical and physical quality of lamb. The success of this study is expected to be a reference using this feed that is high in saturated fatty acids to improve chemical and physical quality of lamb in order to reduce consumers susceptibility to cardiovascular disease.

Animals and Feed
Fifteen of local male sheep aged 9-12 months with a body weight of about 14-17 kg were raised in individual equipped with places to eat and drink. Sheeps were randomly divided into 3 groups according to the treatment of feed; each group consisted of 5 animals. Completely randomized design was used in this study.
Basal diet was consisted of forage and concentrate with a ratio of 60:40. Forage used was elephant grass, while the concentrates were consisted of 30% rice bran and 10% soybean meal. Nutrient contents of basal ration were 62.98% of total digestible nutrients, 45.5% of dry matter, 14.48% of crude protein, 4.70% of crude fat and 21.93% of crude fiber. The first group received only the basal diet (R0), the 2 nd group received the basal diet and 3% of CPO (R1), while the 3 rd group received the basal diet and 3% of CPO protected with 2% formaldehyde (R2).

Chemical and Physical Meat Properties
After feed treatment for 3 months, sheep were slaughtered. Halal slaughtering is done, starting with the neck cut to the jugular vein severed, esophagus, and trachea (near the lower jaw bone). The Longissimus dorsi (LD) muscle on the back of the carcass were taken for analysis of chemical meat composition (AOAC, 2005) and meat physical properties, consisting of pH (AOAC, 2005), water holding capacity using Hamm's method (Soeparno, 2005), tenderness with Warner Bratzler tools and cooking loss (Suryati et al., 2008).

Data Analysis
The data were analyzed by analysis of variance. The differences between treatments were tested further by Duncan's New Multiple Range Test. Data processing was done by using the SPSS program 17.0 for Windows Evaluation Version (Oramahi, 2008).

Chemical Composition of Meat Water Content
The effect of CPO protected by formaldehyde on water content of lamb is presented in Table 1. The results showed that the addition of CPO in the basal diet (R1) caused a decrease in the water content of the meat (P<0.05) about 1.76% compared to sheep that were given basal diet (R0). The decrease in water content was much higher (P<0.05), i.e. 2.83%, in sheep fed CPO protected with formaldehyde in the basal diet (R2), but it was not significantly different than that of R1. The decrease in water content was due to an increase in fat content that was negatively correlated to the water content. The water content in this study ranged from 73.95 to 76.78%. Water is the largest component of meat, namely 75% (Lawrie, 2003) with a range of 60-80% (Forrest et al., 1975). Manso et al. (2009) reported that the addition of sunflower oil (SFO) in Merino sheep diet obtained 75.20% of water content.

Protein Content
The effect of CPO protected by formaldehyde on protein content in lamb is presented in Table 1. The results showed that the addition of CPO in the basal diet (R1) causes an increase in protein levels (P<0.05) by 0.82% compared to sheep that were given basal diet (R0). The increase of protein content was much higher (P<0.05), i.e. 1.41%, in sheep fed CPO protected by formaldehyde in the basal diet (R2), but it was not significantly different than that of R1. The increase is due to increase of rumen microbial protein that might accumulate in the meat, it was caused by the availability of N, the source of energy and carbon skeleton as a precursor for the synthesis of microbial protein (Tiven et al., 2011). The increase of this protein content in line with Kitessa et al. (2003) who reported that protected tuna oil (PTO) with formaldehyde can increase the protein content of milk in lactating sheep from 54 g/kg to 56 g/kg.
The protein content in this study ranged from 18.21 to 19.62%. Meat contains protein by 19% with a range between 16-22% (Forrest et al., 1975). The results of this study is higher than the research of Manso et al. (2009) which added hydrogenated palm oil (HPO) and sunflower oil (SFO) in Merino sheep diet, obtained the protein content of 17.63% and 19.27%.

Fat Content
The effect of CPO protected by formaldehyde on fat content in lamb is presented in Table 1. The results showed that the addition of CPO in the basal ration (R1) increased the fat content (P<0.05) by 0.71 % compared to sheep that were given only the basal ration (R0). This increase is due to the extra fat from palm oil in the diet. Increase of fat content was much higher (P<0.05), i.e. 1.27%, in sheep fed CPO protected with formaldehyde in the basal ration (R2). The increase is due to formaldehyde can protect CPO fat; especially unsaturated fatty acids and reduce microbial degradation in the rumen, so that it can accumulate in the meat. The protection of CPO with formaldehyde can increase unsaturated fatty acids, i.e. oleic, linoleic and linolenic acid (P<0.01) (Tiven et al, 2011). The increase of fat content is in line with the research of Kitessa et al. (2003) which protected tuna oil (PTO) with formaldehyde, can increase the fat content of milk in lactating sheep from 74 g/kg to 77 g/kg.
Fat content in this study ranged from 3.12 to 4.39%. According to Forrest et al. (1975), meat fat content is about 2.5% with a range between 1.5 to 13%. The results of this study is higher than the research of Manso et al. (2009) which reported that the addition of hydrogenated palm oil (HPO) and sunflower oil (SFO) in Merino sheep rations, gained fat content of 2.46% and 3.20%. According to Savell and Cross reported by Soeparno (2005), the fat content of beef accepted by the consumer is about 3-7%. Referring to the statement, the lamb produced in this study might be accepted by consumers, because the fat content is within that range.

Ash Content
The effect of CPO protected by formaldehyde on ash content in lamb is presented in Table 1. The results showed that the addition of CPO in the basal ration (R1) and CPO with formaldehyde in the basal ration (R2) were not significantly affect on ash content of lamb. The average ash content in this study was 1.35%. The ash content is also influenced by the fat content, which is negatively correlated to the ash content. According to Forrest et al. (1975), ash content was influenced by the fat content, the higher the fat content of meat, the lower the ash content. The addition of sunflower oil (SFO) in Merino sheep diet, gained 3.20% of fat content and 1.64% of ash content, whereas the diet without the addition of oil (control) gained 2.73% of fat content and 1.79% of ash content (Manso et al., 2009). Most of the minerals relatively contained in lean meat because mineral components were primarily associated with water and meat protein (Soeparno, 2005).

Meat Physical Properties Meat pH
The results showed that the addition of CPO in the basal diet (R1) and CPO protected with formaldehyde in the basal diet (R2) were not significantly affect on meat pH ( Table 2). The average value of meat pH was 6.22, that was higher than the ultimate meat pH, with a range of 5.8 (Soeparno, 2005). The high value of ultimate pH was due to low muscle glycogen reserves when it was slaughtered so that the accumulation of lactic acid stopped, because muscle glycogen reserves was exhausted before the meat ultimate pH was reached. Stress before slaughtered, such as: weighing livestock, can reduce muscle glycogen. According to Lawrie (2003), glycogen can reduce because the livestock are tired, hungry or scared before slaughtered. This pH value is lower than the study of Cooper et al. (2004), which used protected linseed and soya bean (protected linseed and soybean -PLS) with formaldehyde in sheep diet obtained meat pH value of 6.52 at 45 minutes after slaughtered, whereas after 24 hours the pH value became 5.68.

Water Holding Capacity (WHC)
The effect of CPO protected by formaldehyde on lamb WHC is presented in Table  2. The results showed that the addition of CPO in the basal diet (R1) and CPO protected with formaldehyde in the basal diet (R2) were not significantly affect on meat WHC. The average value of meat WHC was 25.47%. The value of WHC was influenced by the meat pH. Large drop of postmortem pH will affect on WHC, i.e. the higher of ultimate pH, less of WHC (Lawrie, 2003).

Tenderness
The effect of CPO protected by formaldehyde on lamb tenderness is presented in Table 2. The results showed that the addition of CPO in the basal ration (R1) was not significantly affect on the tenderness of lamb compared to those that were given only the basal diet (R0). However, the addition of CPO protected with formaldehyde in the basal ration (R2) made the lamb become tenderer (P<0.01) compared to lamb from sheep given only the basal diet (R0) and sheep given the basal diet with the addition of CPO (R1), each at 3.93 kg/cm 2 and 2.69 kg/cm 2 . Better meat tenderness in treatment R2 was affected by the higher of saturated fatty acids content, compared to R1 and R0. Mauger et al. (2003) stated that the high saturated fatty acids caused ruminant fat becomes harder and can lead to cardiovascular disease in consumers.

Cooking Loss
The effect of CPO protected by formaldehyde on lamb cooking loss can be seen in Table 2. The addition of CPO in the basal diet (R1) was not significantly affect on meat cooking loss, compared to meat from sheep given only the basal diet (R0). The addition of CPO protected with formaldehyde (R2) in the diet made cooking loss that was lower (P<0.01) than lamb from sheep given only the basal diet (R0) and lam from sheep given the basal diet with the addition of CPO (R1), each at by 7.63% and 7.98%. The low meat cooking loss on R2 treatment was influenced by the higher fat content of meat compared to R0 and R1 (Table 2). According to Forrest et al. (1975), that the cooking loss was influenced by the fat content in meat and fat translocation.
During cooking, the fat will melt and distributed in the meat so the meat that has marbling will have smaller cooking losses. According to Soeparno (2005), the equitable distribution of fat throughout the meat can act as a barrier liquid to escape during cooking. Generally, cooking loss varies with the range of 15-40% (Soeparno, 2005). The meat with low cooking loss relatively has a better quality than the meat with high cooking loss, because of little nutrients loss during cooking.

CONCLUSION
The CPO protected by formaldehyde in the diet can increase meat protein and fat content, and produce tenderer lamb with lower cooking loss.