The effects of savory essential oil on rumen fermentation and yield in West Azarbaijan native goats (Mahabadi)

Dissertation for Master's Degree

Livestock and Poultry Nutrition

Abstract

This research aims to investigate the effect of different levels of savory essential oil including levels (zero mg, 200 mg, 400 mg) and type of grain (corn and barley) on the fermentation process. Rumen, animal performance and some blood parameters of native goats of West Azerbaijan were done. In this experiment, 36 female goats native to West Azerbaijan were used. The experimental ration was set as two rations based on barley and corn. The experimental design used was a 3x2 factorial experiment in the form of a randomized complete block design for 11 weeks. The results showed that the effect of savory essential oil and grain type on dry matter consumption, weight gain and food conversion ratio is not significant (P>5%). Between the rumen fermentation factors, the treatments had a significant effect on the concentration of total volatile fatty acids in the rumen. So that the highest average of the essential oil level was 400 mg of essential oil with 101.28 mmol and the lowest average was 200 mg with 85.77 mmol. In terms of cereal grain, the highest value is related to barley grain and the lowest average is related to corn grain. Acetate in the rumen also had a significant difference between the treatments (P<5%). So that among the levels of essential oil, the highest average was related to the level of 400 mg with 63.40 mmol and the lowest value was related to the level of 200 mg with 47.58 mmol. The effect of essential oil levels on ammonia nitrogen was also significant. So that the highest average was related to zero mg level with 7.74 mg/dL and the lowest average was related to 200 mg with 4.61 mg/dL. The pH level of the rumen fluid was affected by the type of cereal grains (P<5%). Blood glucose was significantly different under the influence of essential oil levels. So that the highest average was related to the zero mg level with 81.94 mg/dL and the lowest value was related to the 200 mg essential oil level with 75.45 mg/dL. In general, the results of this experiment showed that the savory essential oil and the type of cereal grain have the potential to influence the rumen fermentation pattern.

Today, the human population is facing rapid growth, which is an explosion compared to the 19th century. This increase in population is important for experts in agricultural sciences and natural resources from two aspects. The first goal is to achieve the technology of human food supply for the world's population and the effective factors affecting their amount and supply, and the second is to study the population increase and its effects on the supply of agricultural products for future generations. In this regard, various issues should be considered, for example, the limitation of arable land and environmental problems and excessive use of limited resources are among them (Taghizadeh, 2015). Considering the complexity of protein digestion and metabolism in ruminants due to the presence of microbial digestion and its many changes in the digestive system, it has a special complexity, experts try to make the animal produce the most protein it needs at the lowest cost in terms of microbial and real protein (Kamra et al., 2008). Tests to measure digestibility include tests on live animals [1] and laboratory methods [2], each of which has advantages and disadvantages in turn.

In ruminant nutrition, a concentrated production system should be considered, especially regarding the production of milk and other animal needs by high levels of energy and protein. Therefore, a high proportion of starch and high quality protein should be used in feeding animals. These materials ferment very quickly. Rapid breakdown of starch causes acidosis and rapid breakdown of protein causes production of rumen ammonia and ultimately increases nitrogen excretion. In the past, in order to delay the degradability of protein, antibiotics were used to reduce the population responsible for rapid protein fermentation. But due to the remaining of antibiotics, the remaining of these substances in animal products and finally the spread of genetic restrictions, their use has been criticized (Ojav, 2003).Finally, the use of antibiotics as growth promoters in animal feed was banned by the European Agricultural Association in 2006. For this reason, scientists were inclined to They found the use of other microbial population control methods (in order to balance rumen fermentation). Plant extracts and essential oils can have a mutual effect on the microbial cell membrane and hinder the growth of some Gram-positive and negative bacteria. As a result, adding the extract and essence of some plants to the rumen will lead to inhibition of deamination and methane production. This action reduces the amount of ammonia, methane and acetate and increases the amount of propionate and butyrate. (Kamra et al., 2008; Patra et al., 2006). In recent years, research on the activity of plant secondary compounds as natural food additives has been of particular interest to nutritionists and ruminal microbiologists (with the aim of manipulating rumen fermentation through the removal of protozoa, methane-producing bacteria and improving protein metabolism and ultimately increasing the efficiency of the ruminant animal) (Kamra et al, 2000; Hart et al 2008, Kalsamyglya et al, 2007; Penn Char et al) 2007; Patra et al, 2006: Mkayntash et al, 2003) when "traditional veterinary drug trials" [3] focused on restoring health to animals and thus indirectly improving the production efficiency. Issues of interest in animal production traits were focused on improving the production efficiency of animals that were healthy and did not show signs of disease. During the last 60 years, one of the ways to improve performance was to introduce low levels of therapeutic antibiotic doses (2.5 to 125 mg per kg of feed, which is 5 to 10 times lower than their therapeutic dose) in animal feed, which could increase their growth efficiency by 10% (Russel and Hoilihan, 2003). And they all belong to the family of ion-loving antibiotics. They are mainly used in raising meat animals and especially in animal fattening. Due to the possibility of antibiotic residues in milk, their use in dairy cattle is restricted. Their mode of action is to disrupt the gradient of ions from the cell membrane of susceptible bacteria (that is, the bacteria that these antibiotics specifically act against) (especially Gram-positive bacteria) and the result has been beneficial changes in the rumen fermentation pattern (Rosol, et al, 2003; Kalavy and Tdschy et al, (2003) the ratio of propionate to acetate production has increased, which is accompanied by a decrease in methane production and a decrease in the degradability of feed protein in the rumen. and both of these increase food yield, and these substances also reduce the incidence of acidosis and flatulence.

However, due to the importance of the issue of bacterial resistance to antibiotics, the use of growth-promoting antibiotics has been banned in the European Union, so plant essential oils are used because of their antimicrobial effects ((Hu Lin, et al, 2004; Burt et al, 2000; Dorman and Deniz et al, 2000 can be one of the substitutes. It seems that the effect of different essential oils on animals is different based on different diets. In a research, lambs fed with a diet based on barley had a tendency to decrease pH in the rumen. This corresponds to the higher concentration of volatile fatty acids in lambs fed with a diet based on barley compared to lambs fed with a diet based on corn. (Chaves et al; 2008) On the contrary, Benjamin et al. reported that the pH and concentration of total volatile fatty acids in the beef cattle fed with a diet based on corn were lower and higher than the treatment fed with a diet based on barley. which was probably caused by the higher dry matter consumption of cows fed with corn-based diet. Beauchemin et al; 2005) (Chaves et al. reported in 2008 that the molar ratio of acetate, propionate, valerate and butyrate in growing lambs was not affected by the type of grain and carvacrol and cinnamaldehyde essential oil. (Chaves et al; 2008). The purpose of this experiment was to investigate the effect of savory essential oil based on corn seed and barley seed diet on rumen fermentation, blood metabolites and performance. Female goats are native to West Azerbaijan.