Feed Imaging: Seeing is Believing

Feed Imaging: Seeing is Believing

With rising raw material costs and never ending disease problems, the future landscape for doing this business profitably will be dauntingly more challenging. Rising feed additives costs, and inconsistent feed ingredient quality add more difficulties and uncertainties to the sustainability of poultry farming.

Feed Imaging article authorsLet’s face this fact and ask the golden question “What more can be done to improve farm productivity and profitability?”. We cannot control rising ingredient costs, so the only thing left is to look inwardly for a better understanding of feed processing and the economic benefits of improving processed feed quality.

This article addresses an area of feed processing which many in the industry are most likely not aware of, due largely to the generally well accepted norm in feed processing and assessment of feed quality.

Feed Imaging exposes problems that could well explain the issues with high feed costs, poor farm productivity, and low survival rate. This forensic science also provides a much better post-mortem insights into the quality of processed poultry feed over current analysis – wet chemistry analysis for starch gelatinisation, PDI and Maillard Reaction.

Feed Imaging shows up accurate visual macro details for assessing the processed feed quality:

1) Poor Processing of Starch/Protein – This affects pellet binding, energy value and feed intake. The feed pellet could be very stable, but if intra-particles bonding is poor in the entire pellet, fines and dust can easily fall off while the pellets are being handled. Also feed intake in farm is directly related to texture of the pellets, 50% of pellet rejection incidences at farms are related to the texture of the pellets. Poorly processed starch and protein directly affects pellets texture and its intake at farms which will certainly affect the farm performance.

2) Maillard Reaction – Reaction of lysine/ and some other amino acids with reducing sugars such as glucose. This reaction impacts protein quality, critical for poultry nutrition. Certainly, we know that Maillard reaction binds lysine, making it non-reactive, and interferes with the transport of stored nutrients to the muscle for growth.

Maillard compounds have many negative effects on the poultry health as well as effects on absorption and storage of nutrients, synthesis and secretion of several enzymes for food digestion.

Stages of gelatinisation benchmark
Figure 1. Stages of gelatinisation benchmark

No More Guessing and Assuming that everything is fine!

• Changes in morphology of maize starch granules throughout the gelatinisation range, showing birefringence when observed under digital light microscopy

• As starch starts to gelatinise with sufficient moisture and heat, we start to observe an increase in granule size, loss of integrity, granular disruption and the eventual loss of birefringence.

• Finally, with the microscope image showing up the glass transition surface

Image of a typical pellet
Figure 2. Image of a typical pellet

What this image of a typical feed is telling us?

1) Starch poorly processed – Clear birefringence, moisture not penetrating the starch granules

2) A high degree of visible crystalline starch – Whitish streaks clearly indicating a lack of moisture hydrating the starch granules. When sufficient moisture penetrates the granule, the amorphous regions of the granules absorb the moisture and swell, resulting in the separation of starch chain from the crystallites. Sufficient water lowers the starch melting point and result in quick melting of the crystallites at high temperature.

3) Darkened colour – Clearly indicating browning from Maillard reaction. Sufficient moisture prevents the breakage of glucosidic-bonds holding glucose to carbohydrates. The Maillard reaction occurs when breakaway free glucose reacts with lysine.

Maillard reaction in feed processing
Figure 3. Maillard reaction in feed processing. When feed containing starch is cooked, the heat can break glycosidic bonds linking the glucose units together and effectively break-up the polysaccharides to release the glucose monosaccharides, which ultimately leads to the Maillard reaction in feed processing.

What is the problem with the current pelleting process?

Feed pelleting is a complex, semi-dry thermal processing, rendering it impossible to deal with the objective of processing starch and protein well, without the dreaded Maillard reaction problem.

The industry has been working under the notion that the feed has been processed well enough, but feed imaging now shows up the problems clearly. Feed pelleting is merely a forced feeding of hot-moist conditioned mash through the die, and at best, only the pellet surface is anywhere close to being better cooked due to high surface moisture and searing effect from the hot die surface. Hence, Pellet Durability Index (PDI) is merely a measure of the strength of the outside of the tube (integrity of the pellet surface). Putting a knife through a pellet often reveals a brittle exterior and very loosely bonded centre, as shown by feed imaging. This is the reason PDI improves when there is more surface moisture in the hot mash and with the higher die compression used for pellet production.

We are seeing abnormally high issues with the starch in the processed pellets. The whitish streaks and rough pellet surface are good indicators that things are not quite right. These weaknesses are clearly observed on all feed put under the microscope. Some obvious factors such as low moisture at conditioner, high temperature processing and high die compression make things worse.

In a very different context away from current industry norm, the main objective with feed processing should be:

  • Induce positive chemistry changes to starch and protein
  • Minimise the negative chemistry changes caused by Maillard reaction.

Using these fundamental principles, the next steps are to deploy the sciences needed to get the job done correctly and optimally.

Summary diagram on the pivotal role of feed processing to feed quality.
Figure 4. Depicts a summary diagram on the pivotal role of feed processing to feed quality.

Moisture plays a very important role in feed processing. It is one of 3 elements involved in cooking food – Heat, Moisture, Time. An effective moisture management technology determines if moisture will be used “functionally”, which greatly determines production efficiency and the processed pellet feed quality. Moisture can only be functional if it is being drawn into the feed chemistry…. Contributing to positive chemistry changes to starch and protein.

Results taken from 2 different approaches
Figure 5. Above image is the results taken from 2 different approaches. Treatment X with a “Surfactant Product” / Treatment Y with positive “Mash Hydrolysation” Concept.

Mash Hydrolysation TM

The whole Science around feed pelleting is centered around the proper hydrolysis and cooking of starch and protein. For this to happen, moisture need to get into the feed chemistry. However, the polarity of water molecule alone is insufficient to disrupt the hydrogen bonding of starch and protein structures.

A group of chemicals which contain divalent cations termed as “structure breakers” with a high charge density having the ability to disrupt hydrogen bonds of starch and protein. These cations also possess high polarity, thus attract water molecules strongly. With the disruption of hydrogen bonds, moisture can penetrate freely into the starch granule, leading to swelling, rupture, and the melting of amorphous and crystalline starch ……leading to starch gelatinisation irreversibly. Such bio-chemistry solution is important for activating moisture into the feed chemistry in the semi-dry feed pelleting process.

In the current low moisture scenario, when water molecules do not easily penetrate into the starch granules and can’t stay retained in the feed chemistry even after higher moisture addition in the mixer, Feed Imaging can easily work as a torch bearer to help feed millers gauge their pellet quality and to know how good they are able to use this added moisture to improve the feeding value of pellets.

Control and Treatment

Authors: Steven Goh and Dr Naveen Kumar, Delst Asia

For more details, write to drnaveen@delstasia.com

Previous article by author: Understanding Recent Feed Refusal And Poor Feed Intake

Pellets: “High Fines” Might Exaggerate Diseases at Poultry Farms

Pellets: “High Fines” Might Exaggerate Diseases at Poultry Farms

Pelleting is system of a modification of the mash system by mechanically pressing the mash into hard dry pellets or “artificial grains”. It is generally accepted that, compared to mash, the feeding of pellets improves feed conversion, broiler performance with an increased feed intake.

Dr Naveen Kumar
(author)

Reasons for the enhanced performance may be due to increased digestibility, decreased ingredient segregation, Decreased feed wastage, reduction of energy during prehension and improved palatability and so the modern broiler industry has traditionally fed a pelleted diet to birds. The quality of pellets must be taken into account also because feeding pelleted rations is not enough to ensure enhanced performance of poultry but also the proper growth, immunity and health status of the bird. There are a number of excellent methods to objectively measure and record the quality of pellets during the manufacturing process.

Other disadvantages of poorly formed pellet includes:

  1. Dusting potential
  2. Flow properties and proportioning gets impaired by fines
  3. Remainders in silos, bins and pans will be increased by fines
  4. Fines and dust are preferred nutrients and habitats for germs and micro organisms of any kind

High fines in the pellet can be a menace and mainly attributed to the issues of “soft pellets” at the press. Improving pellet hardness or durability is an effective means of reducing fines. Pellet durability may be improved by manipulation of diet formulation and improving feed manufacturing practices. Feed manufacturing practices adjusted to suitable to ambient climatic conditions and native ingredients will have a profound effect on pellet durability and potentially involve less expense than changing raw materials or using pellet binders.

Further the economic aspect of moisture retention in feed processing is strongly recognized but there are several other interesting aspects attached with this moisture content of the feed as well. One of them is its consequence on keeping quality and duration for how long it stays fresh. Nothing beats a freshly cooked meal, and this holds true not only for humans, but for animals, too.

Feed Processing role

Feed components start deteriorating as soon as they undergo the feed mixing process. Feed exposed to high temperature (and) or high humidity, or feeds containing increased levels of sensitive ingredients, will have a reduced shelf life. Cooked starch starts looking “stale” as soon as it cools down, Vitamins starts loosing potency almost instantly when intermixed with certain trace minerals, fats and lipids start oxidizing as soon as they come into contact with air and this is why it is important to control water activity (aw) of feed to keep these vital nutrients intact and keep the feed remain fresh till it is consumed. It is not that feed becomes unsuitable to consume so fast but it is the significant loss of micronutrients from mixing of feed to actually consume by the hyper producing birds.

Respiratory Challenges/ Ascites:

Because of poor pellet quality and reduced hardness, fines up to 50% have been reported from the field conditions. These incidences of high levels of fines in the field are not only associated with poor live weight and FCR but also has huge dusting potential posing respiratory challenges. The fines in the feed are inhaled by the birds and while exhaling they settle in various part of air sacs, specially thoracic air sac where air stays for longer period which leads difficulty for birds to breath hence deficiency of oxygen in the blood.

Further mold spores appear almost immediately within 12-24 hours after the bagging of the feed in field conditions. The moisture content of the feed usually ranges from 10 – 12%, which when exposed to environment and retained in the pans as uneaten leftover for a week or more before it is consumed in automated feed system gets heavily contaminated with mold spores. Birds fed with lots of fines in feed with increasing mold spores infestation and placed in environments contaminated with aerosolized conidia (mold spores) may show significant pathology after only a short duration of exposure.

Anatomy and physiology of the avian lung-air sac system are strikingly different from that of the broncho-alveolar Aspergillomalung of mammals. Avian air sacs are particularly prone to contamination because they are submitted to an airflow that favours particle deposition. Mold spores are small enough, 2-3 μm in diameter, to bypass initial physical barriers and disseminate deeply in the respiratory system.

It has been suggested that the dust created by the fines of the feed and mold appeared in the stale feed respiratory damageget inhaled by the birds during increased number of pecking, leading to irritation and reduced efficiency of the airways. Poor air quality, environment dust and respiratory diseases also impairs the perfusion capacity of chicken lungs, creating an imbalance between oxygen supply and the oxygen required to sustain rapid growth thus predispose birds to ascites by causing respiratory damage.

Ascites is a disease, which causes death in poultry apparently because of fluid retention. Ascites is commonly known Ascitesas “water belly”. There is no known cause and no apparent cure. There are theories that the amount of heat in the early days of the chicken or turkey’s life, or stress, may be the cause of ascites but there is no significant data to support these theories. However, invention with antifungal agents to reduce the symptoms associated with ascites and preventing mortality from the disease confirms the role of mold and its spores as a major causative factor for the ascites.

The commercial broiler of today represents the culmination of dramatic changes over the past 60 years. Genetic selection processes that focused mainly on production traits putting heavy pressure on the bird’s cardio respiratory system and immunity.

Increase in metabolic rate, coupled with exposure to environmental conditions such as temperature, lighting and ventilation, and nutritional factors such as feed form or fines into it, all seem to promote the development of ascites. The primary cause of the ascites syndrome, however, is believed to be hypoxia/hypoxemia when the bird’s demand for O2 exceeds its cardiopulmonary capacity and causes pulmonary hypertension, which results in development of the ascites syndrome. Inadequate ventilation and dusty feed increase the risk of bird exposure to aerosolized spores. Acute cases are seen in young animals following inhalation of spores, causing high morbidity and mortality. The chronic form affects older birds and looks more sporadic.

Crop Mycosis or Mycotic Diarrhea

Crop mycosis or Mycotic Diarrhea is a reference to a condition called Sour Crop that is caused by a type of yeast called Candida albicans. This causes thickening of the crop surface characterized by whitish thickened areas of the crop and proventriculus and may keep nutrients from being properly absorbed from the intestinal tract. It may lead to destroy the tissues of the upper digestive tract particularly the crop and gizzard. It is believed that in severe cases the disease may also infect the intestinal tract. Feeds and fluids may retained in the crop, causing it to enlarge. The orientation of the crop of a chicken is such that any feed or water consumed tends to flow past and contact the crop. Particularly, an environment which is warm, moist, possesses a neutral pH, contains oxygen, includes a substrate which enhances yeast growth.

Poultry of all ages are susceptible to the effects of this organism. The disease affects primarily broilers, laying hens and turkeys. Mycosis is transmitted mainly by ingestion of the moldy feed, water or environment. The organism grows especially well on corn-based diet, so infection can be introduced easily by feeding stale feed. Crop Mycosis may also be “triggered” by the use of high levels of antibiotics in feed or drinking water for treatment of other bacterial diseases like CRD, Necrotic enteritis, colibacillosis etc. Continued use of antibacterial agents in poultry to prevent and treat increasing bacterial infections often causes secondary fungal infection, giving chance to mold spores appeared in the feed during transit and storage to colonize and multiply in the crops as feed stays longest in the crop (approximately 90-100 minutes). Birds/flocks who have been on antibiotics for a period of time are the easiest target of crop mycosis, fed on caked or stale feed.

Crop Mycosis

This malady produces no specific symptoms. Young chicks become listless, pale, show ruffled feathers and appear unthrifty. Affected caged layer hens become obese and anemic. Clinical signs include dull and depressed look, reduced feed intake, poor growth often with large fluid filled crops and foul smelling odor emitted around the mouth. Profuse diarrhea may be noted. Losses are due to reduced feed efficiency, increased mortality (from 5%-20%), poor performance and stunted growth. Some birds also exhibit a vent inflammation that resembles a diarrhea-induced condition having whitish incrustations of the feathers and skin around the area. Feed consumption may increase by 10% to 20%.

Diagnosis is based upon clinical signs and relevant history. Gross lesions are mostly confined to the crop, proventriculus and gizzard. The crop and proventriculus have whitish thickened areas that are often described as having a “turkish towel” appearance.

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Erosion of the lining of the proventriculus and gizzard is commonly observed, as well as an inflammation of the intestines. Mycotic lesions in young poults and chicks may be so small as to be easily over- looked during postmortem examination. Additional tests such as crop histopathology or microscopic examination of crop smears (mixed with KOH 10% and heated) will diagnose if Fungi is the cause however are rarely done due to time and financial constraints.

Once introduced into the flock, mold/yeast is perpetuated by suboptimal management conditions. Preventative measures include the continual use of a feed preservative & mold inhibitors in the feed, proper feed handling and storage, daily cleaning and sanitizing of the watering system.

Mycotoxins & Toxicity:

Mycotoxins are often accumulated in the feed dust as they offer a very favourable condition for mold and fungus to grow and exposure to it can have toxic effects on all farms animals including Poultry. Consumption of mycotoxins-contaminated feed causes a plethora of harmful responses from acute toxicity to many persistent health disorders with lethal outcomes. Effects of a mycotoxin on poultry depend on the mycotoxin type, level and duration of exposure and age. Acute toxicity is caused by intake of high doses of mycotoxins and is characterized by death and well-described clinical signs. Most prevalent Aflatoxins are reported to cause reduced bird performance, lower immunity, organ damage, and reduced egg production. Therefore, the main task for feed producers is not only to carefully select raw materials based on the nutritional quality, safety, price, and availability but to also minimize the concentration of mycotoxin in formulated final feed by applying right processing knowledge and strategies aimed at minimizing the risk of fines in final bagging and mycotoxin effects on animals and human health. Challenging climatic conditions characterized by high relative humidity, high temperatures, and more free water in the final feed aggravate the mycotoxins biosynthesis by toxigenic fungi in the feed with high fines percentage.

Conclusion:

Although improved broiler performance is an advantage for pellet feeding, some disadvantages seem to be connected to feeding poor quality pellets to the birds. With respect to animal health, a correlation between poor quality pellet feeding with lots of fines in it and the occurrence of certain diseases cannot be ignored. Nutritionist plays an important role in poultry industry to achieve the genetic potential of these hyper performing birds. As the industry has always been working from a feed formulation perspective and Nutritionist’s and feed manufacturers spend much time and effort in evaluating the formulation, and feed additives but the final pellet quality.

It is important to realize here that feeding low quality pellets or crumble to the “new and improved” poultry can potentially do irreversible damage. Since poultry have the highest rate of gain early in life, they need nutrient-dense diets that support the rapid growth rate without challenging their health status. Feeding for least cost without focusing quality of crumbles and pellet in the first two weeks can result in lost performance that is never regained.

Not only is a proper nutritional program critical, but also a strong quality control program is a must to assure that quality ingredients are received and high-quality feed produced. This is as important for macro-ingredients such as corn, soybean, fat and animal proteins sources as it is for micro-ingredients such as vitamins, amino acids and trace minerals. It is also crucial to ensure that the feed mill delivers durable pellets and crumbles with a minimum amount of fines to encourage feed consumption.

Properly formulated feeds are worthless if birds do not eat the feed as a complete meal packet (a pellet or crumble). Finally, as the number of disease outbreaks are on rise and use of antibiotics for bacterial challenges is becoming limited, it is important for the vets as well to explore alternative options to keep the feed fresh and pathogen free to offset disease challenges.

Feed formulation no doubt is the focus point of this business, but raw material handling and feed processing plays a huge part on feed quality, and hence the performance & bottom line. A correct and pro-active approach will help save the industry much monies from unnecessary wastage from raw material quality, contamination, the unnecessary use of feed additives, over-formulation to compensate for the nutrient loss in feed processing and post processing quality issues, plus the avoidable use of medications at farm level. Controlling water activity (aw) values of the poultry feed, within safer limit, could be an extremely important consideration, in order to produce a safe and hygienic feed that is both commercially viable and since it plays an effective role in the physical, chemical and biological stability of the product.

About the author:

Dr Naveen Kumar, B.V.Sc & A.H (Gold Medalist), M.V.Sc (IVRI, Bareilly) is a food & oil seed grains storage specialist and a finished feed quality expert for Asian and other tropical countries. He also Business Director of Delst Asia and is located in Faridabad, India. He can be reached at naveensharma21@gmail.com,  Mobile +91 93502 89123.

Title Image Source: BG-Studio Shutterstock.com 

Another article by author: Introducing Water Activity As A Measure For Feed Quality Control (Part 1)