Synopsis: The article discusses about the importance of liver health and how phytochemicals can effectively prevent liver dysfunctions and help in optimum egg production.

Because the liver produces the egg yolk precursors, liver health is critical for optimum egg production. A strong egg production capacity is linked to a healthy liver. The liver is involved in the activation of vitamin D3, which has a direct impact on calcium metabolism and eggshell quality.

Liver: Central Organ of the body

The liver is a large and vital organ that plays a key role in nutrition. It is one of the busiest organs in body primarily involved in lipid, protein, and carbohydrate metabolism & detoxification. It can also store a variety of fat-soluble vitamins (A, D, E, and K), as well as water-soluble vitamins (B1, B2, and B12) and minerals (Fe and Cu). In addition, the liver is engaged in the activation of vitamin D3 in order to increase calcium absorption for the development of eggshells. Furthermore, the liver is necessary for the conversion of poisons into water-soluble waste products that can be eliminated through the kidneys.

Agents causing Liver Damage

• Toxic metabolic byproducts of fungus infestation on grains are known as mycotoxins. Fungal growth and toxin synthesis can occur when grains have a high moisture content. Toxins can be produced by fungi either before or after grain harvest. Moderate to severe liver damage is caused by eating grains that contain fungus generating toxins. Aflatoxin-related liver lesions include enlarged fatty livers with bleeding and anaemia. An inflamed, bright red to yellow hemorrhagic liver is one of the symptoms linked with trichothecenes from Fusarium fungi. Aspergillus and Penicillum create ochratoxin, which is the second most common toxin. Fatty liver with bleeding and urate deposits on the liver are among the Ochratoxin-related symptoms.

• A range of liver disorders are caused by nutritional deficiencies or imbalances. Anti nutritional factors (ANF) may be present in the diet, preventing feed absorption, use, or metabolism. These ANF produce varied degrees of liver damage due to excessive lipid peroxidation. Fatty liver can be detected in birds given a high-energy, low-protein diet, and liver parenchyma haematomas are common in cage layer exhaustion.

• Higher ambient temperatures lower energy demands, resulting in a more favourable energy balance. Birds regulate their body temperature by using evaporative cooling during breathing. Excess belly fat can obstruct regular breathing and cooling, making these birds more susceptible to both heat stroke and liver rupture.

• Many bacterial infections affect the liver. Fowl typhoid, which causes significant mortality in poultry, is characterised by an enlarged bronze colour mottled and fragile liver. Tuberculosis in poultry causes caseous necrosis, which is characterised by white, hard lumps of varying sizes in liver. Mycoplasma causes fibrnous perihepatitis, which is the leading cause of economic losses in poultry.

• Inclusion body hepatitis (IBH), Marek’s disease, and Avian Leucosis are the most common viral disorders that affect the liver.

• Other disorders that affect the liver include visceral gout, which is characterised by the presence of chalky white masses surrounding the liver and other organs. In the event of coccidiosis in chicken, multifocal greyish white coalescing lesions can be seen on the liver.

Liver Metabolic diseases

In birds, dietary fatty acids are secreted as portomicrons into the portal blood stream. Portomicrons pass through the liver before reaching the rest of the circulation due to their direct entry into the portal blood stream. This trait causes fat buildup in the liver in birds and exposes the liver to a variety of pathogenic agents and poisons. Liver diseases have far-reaching effects on the performance and health of birds. Hepatosis, necrosis, fatty liver, hepatitis, and cholangitis are the pathological abnormalities that ensue.

Reason behind Fatty liver in poultry

During high blood glucose levels, the liver can convert glucose into glycogen and triglycerides, which are stored as energy. It can break down glycogen to be used as glucose when blood glucose levels are low, which is controversial. Fats and amino acids can also be converted to glucose by the liver. When compared to the usage of fat or carbohydrates for energy, catabolizing protein needs a lot of energy and hence results in a larger heat increment. Fat is broken down into fatty acids and absorbed in the intestines; the majority of these fatty acids enter the bloodstream and eventually reach the liver. In the liver, fat production for yolk lipoproteins is an important step. The buildup of lipids in the liver begins when fat synthesis outpaces fat mobilisation. When it occurs over a prolonged period of time is results into fatty liver syndrome.

Oestrogen is linked to sexual maturity that causes the liver to store more fat for egg yolk production. In reaction to oestrogen levels, the liver size of the bird increases considerably as it enters egg production. The laying bird is predisposed to develop Fatty liver hemorrhagic syndrome (FLHS) due to a combination of positive energy balance and oestrogen impact.

Prevention strategies for optimum liver health

• Avoid overfeeding of energy rich diet. Maximizing calorie intake during the early stages of lay is critical for productivity; however, when production declines, energy requirements will decrease. To keep birds from accumulating too much weight, feed density may need to be reduced. Reduce energy consumption by switching to a lower-energy diet and/or modifying feed management.

• When compared to mash feed, crumbled or pelleted feed resulted in higher feed and calorie consumption. Crumb and pellets should be avoided in flocks that are vulnerable to FLHS.

• To guarantee enough quantities of antioxidants to avoid tissue rancidity, layer diets should contain adequate levels of Vitamin E (50-100kg) and selenium (0.3ppm). Lipotropic agents, such as Choline (500 mg/kg), Methionine (0.1%), and Vitamin B12, aid in the metabolization of fat from the liver and aid in the recovery of damaged hens.

• FLHS has been linked to calcium insufficiency. This can be addressed by supplementing the diet with large-particle calcium and Vitamin D. This permits the bird to consume more calcium without consuming too much of the feed’s energy component.

• Using herbal supplements derived from plants plays a very pivotal role in protecting liver from hazards like excessive antibiotic use, mycotoxins and feed imbalance.

Can herbs protect liver damage in poultry?

With the growing demand for organically raised chicken, using naturally occurring nutrients could be a cost-effective way to increase farm production and health. Many herbs have been studied to have favourable effects on the liver, which can help boost farm productivity.

Some significant herbs with major activity on the liver for its protection and enhancement of functions are discussed in the table:

The nutritionists have been using the phytogenics in recent times to ameliorate the liver dysfunctions and to promote better liver health. Many products like Mintoliv with about 13 phytoactive rich herbs helps in providing liver proper care. These active ingredients act as hepatoprotective, hepatostimulative and hepatoregenerative in action, thus takes care of overall health of liver. Various researchers have found that these herbs act as hepatoprotective in aflatoxicosis, drug toxicity & other toxins and rejuvenates damaged liver tissues. They strengthen sluggish liver during debility, convalescence & anorexia. However, the research is still in infancy and more trials need to be carried to ascertain the mechanism of action of these actives.

Conclusion

Profitability requires maximising animal output according to genetic potential. The liver serves a number of important functions in the preservation of health and the efficient use of feed materials. Combinations of the herbs (as mentioned above) are available for use in poultry as feed additives to avoid liver problems and as a tool to promote feed utilisation, resulting in increased farm output. As a result, nature’s gift, herbal liver tonics, can help chicken farmers achieve optimum productivity based on genetic potential.

More details can be reached at www.nutricare.in

Other articles by Dr. Vandana Sharma: Toxin Management: Stopping Hidden Threat In Feed

One of the most significant ways of enhancing nutrient digestibility is the use of enzymes. In most practical diets for poultry, the three most expensive nutrients are: energy, protein, and phosphorus. Although we have managed to procure successful commercial enzymes that enhance the efficiency with which birds derive energy and phosphorus from their feed, the animal nutrition industry has not been so successful in the case of protein. In truth, early attempts have been more than disappointing for many enzyme producers.

There are several reasons for this, including inadequate research and development, difficulties in producing a commercially viable enzyme, and of course, the uphill battle against the naturally high digestibility of most conventional feed ingredients. Birds are already digesting their feed quite well! However, the largest failure must have been the lack of resources and perseverance.

Why a protease?

The most obvious question that we must first answer is why poultry diets require such an enzyme. The answer is quite clear when profitability comes into the picture particularly in today’s scenario where the raw material prices are sky rocketing. Today, the technology of producing an enzyme has advanced to such a high degree that it makes it economical to use enzymes even under the most unfavorable conditions in terms of feed ingredient prices. For example, the addition of protease enzyme has been shown to reduce feed cost on average by 5%, even after considering the actual cost for the enzyme. In today’s tight financial times, a 5% reduction in feed cost alone can be the key to survival for many operations worldwide.

This reduction in feed cost is achieved by means of lowering protein (amino acids) specifications to consider the improved digestibility of protein in natural ingredients. Thus, the inclusion level of soybean meal, one of the main protein-rich ingredients is reduced, and of course, the need to add synthetic amino acids is also reduced significantly. Of course, the exact savings depend on the actual ingredients used and their prices.

Research has also shown that the use of protease enzyme also improves overall animal performance. This is the result of the beneficial effects of a low-protein diet, which minimizes the metabolic strain of excreting surplus nitrogen, with the added benefit of leaving more dietary energy available for growth. This effect is not a new discovery, unique to proteases, but something well known to scientists for many years and applicable to all monogastric species. Another indirect benefit from the use of a protease that improves protein digestion is that nitrogen excretion in the environment is markedly reduced which is a great advantage for the producers during the winter months. Thus, protease enzyme not only enhances the digestibility of protein, leaving less natural protein undigested, but the low-protein diets used in conjunction with the enzyme are better balanced in terms of amino acids, leaving less surplus to be disposed of through metabolism.

On average, protease enzyme enhances protein & amino acid digestibility by 3-7% and as such it should be expected to reduce nitrogen excretion significantly. Again, these are averages obtained through numerous research trials and field observations in the past ten years of development and use in the field. Actual numbers will differ according to ingredient selection and current dietary protein specifications.

The main reason broiler producers as well as feed producers require a protease enzyme is profitability. Protein raw material prices have shown a sustained upward trend over the last few years. Despite abating a little in the last few months, the general consensus of independent observers is that prices will continue to increase in the future. This is the consequence of consumption exceeding supply on account of demand from emerging economies, and the impact of bio-fuel production on the composition of harvested areas across the world. A protease which can consistently improve the digestibility of amino acids in such materials, thus reducing their inclusion level in feed while maintaining current levels of animal performance, is therefore economically very attractive.

Direct cost savings at the feed mill, however, are by no means the only reason for considering a protease (Figure 1). When a suitably efficacious protease is used, it can be an important contributor to the continued economic viability, sustainability and consumer perception of the broiler industry.

Not all proteases are the same:

For a protease to be successful in feed it should, like any other enzyme, be selected and developed with that specific use in mind. Unfortunately, many of the first proteases entering and, in many cases, still available for use in the feed industry were developed for other purposes. non-specific alkaline proteases initially derived from Bacillus subtillis and developed for the detergent industry, with characteristics which render them less effective in feed.

The recent development of unique feed protease specifically selected for application as a feed enzyme, has overcome many of these issues. Unlike most other commercially available proteases, it is produced from a genetically modified strain of Bacillus licheniformis. In the selection process, factors such as the ability to degrade many different feed proteins; the need to complement the endogenous protease enzymes; activity after exposure to the low pH conditions of the gizzard and proventriculus; and stability during feed processing were all considered.

pH stability:

Probably one of the most important criteria for success of a protease in broilers is good stability under low pH conditions found in the bird’s stomach. The level of viable enzyme reaching the ileum is thus also limited. In contrast, with Bacillus licheniformis derived protease, stability at low pH is greatly improved, ensuring sufficient enzyme activity in the small intestine to give the desired hydrolytic effect.

For a protease to work successfully, it is essential that it should complement the endogenous enzymes. The bird’s stomach and small intestine already produce pepsin and pancreatic proteases, respectively. The exogenous protease must work in synergy with these enzymes to obtain the optimum benefit in all but the very young bird, where endogenous levels may be limiting.

Flexibility of use:

For a protease to be commercially useful it must be possible to use it flexibly in a diverse range of diet types. The ability to improve the digestibility of protein from as wide a range of feed ingredients as possible is therefore important. Protease should have the potential to improve digestibility of protein in a wide range of ingredient sources in vitro. Such improvements should however not just be obtainable in vitro but also in vivo. In vivo, both ileal and faecal amino acid digestibility studies have confirmed the significant improvements in digestibility for a wide range of different raw materials when Protease enzyme is added.

Processing stability

As the conditioning time and temperature during the production of pelleted broiler feeds becomes ever higher and longer to ensure compliance with increasingly stringent food and feed safety requirements, stability of feed enzymes under more extreme conditions is increasingly essential. To this end, for a protease to be successful, thermostability is a must. Protease enzyme is consistently more stable at each of the conditioning times and temperatures tested, demonstrating its superior stability even under more demanding conditions.

Reducing Anti nutritional Factor:

Soybean meal (SBM) is the most important source of dietary protein for poultry it itself contains some antinutritional factors like Trypsin Inhibitor (TI). Although TI is reduced by heat treatment, overheating has a negative impact on protein quality and amino acid digestibility. Exogenous Protease enzymes can improve digestibility of feedstuffs, lower feed costs and improve animal performance. Proteases improve animal performance and nutrient digestibility by decreasing digesta viscosity, improving endogenous enzyme activity and decreasing pancreas weight (Bedford and Classen, 1993; Bedford and Schulze, 1998; Erdaw et al., 2017a,b; Yan et al., 2017).

The determination in the laboratory of the TI content of SBM and its relationship with AA availability is tedious and time-consuming and provides inconsistent results. Also, the traditional processes of treating SBM can’t remove the anti-nutritional factors to a safe level. Therefore, use of exogenous protease is very effective in reducing the deleterious effect of TI in SBM. Liu et al., in 2013 conducted a study wherein they used a protease enzyme (CIBENZA EP150) with different levels of TI and found that protease enzyme was able to destroy almost all trypsin inhibitors (both Bowman-Birk & Kunitz TI) present in soyabean meal (at 1:1 ratio) and destroy substancially even in higher concentración (2:1) of TI as well.

Conclusions:

The benefits of including a protease enzyme in broiler diets are confirmed in numerous published reports. Such research shows that this protease can improve the protein digestibility of a wide range of natural ingredients by 3-7%. Such improvements translate into significant cost savings per ton of feed and are achieved without any compromise on animal performance.

Source: Novus International

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