**4. Advances in nutritional research**

Over the years, researchers have improved or introduced new research techniques in their quest to obtain valid data or keep pace with new challenges confronting the poultry sector. In this section, I will attempt to discuss some of the advances made in poultry nutritional research with the aim of improving productivity and quality of meat/eggs, welfare of birds as well as environmental sustainability. These include modern techniques for feed analysis and nutritional experimentation involving novel feed ingredients and/or feed additives, nano-minerals, mineral toxicity as well as dietary management strategies to curtail problems and constraints of avian health and environment.

#### **4.1 Feed analysis**

The surest way of meeting the nutrient requirements of birds is having adequate knowledge of nutrient contents of various feedstuffs available. This requires feed analysis with regards to nutrient composition and anti-nutrient contents. There

have been advanced techniques employed over the years which give true reflections of chemical composition of feedstuffs that enables nutritionists to be able to accurately formulate diets for all types and classes of poultry. These include improved methods for determination of dry matter, proteins, carbohydrates including fibre, fats/oils and macro-and micro-minerals as contained in the official Methods of Analysis (2019) and published by the Association of Analytical Chemists (AOAC) International [8]. These techniques not only determine the true content of feedstuffs but also saves time and amounts of samples to be analysed as well as minimum operator training. Examples are vacuum-oven drying/toluene distillation of high fat feeds for moisture determination; Automatic Kjeldahl Analyser/Dumas technique (LECO)/Amino Acid Analyser for protein determination; Megazyme enzyme kit for starch determination in cereals; Rose-Gottlieb/Soxflo method for fat determination; Fibre Analyzers for determination of acid detergent and neutral detergent fibres, and the use of Inductively coupled plasma optical emission spectrometry (ICP-OES) analyser for determination of several minerals at the same time; Near-infrared spectroscopy (NIRS) technique for determination of moisture, crude protein, metabolisable energy and digestible amino acids of whole feed sample [8].

The presence of anti-nutritional factors (ANFs) in feedstuffs compromise the potential nutritional value of feedstuffs for poultry. Some have detrimental effects on the health of birds. Thus, identification and quantification of anti-nutrients in feedstuffs through advances made in feed analysis has improved nutritional value of hitherto inedible plant products into useful feedstuffs. For instance, the identification and subsequent elimination of trypsin inhibitors in soybean improved its feed value for poultry substantially. Examples of analytical methods for detecting ANFs are as follows: Yb-precipitation/Vanillin-HCl/4-dimethylamino-cinnamaldehyde (DMACA-HCl)/BSA/PEG/mass spectrometry methods for determination of tannins; High-performance liquid chromatography (HPLC)/Acid–base titration/acid dye colorimetry for determination of alkaloids; and ELISA methods for determination of mycotoxins [8].

#### **4.2 Feed formulation**

Feed formulation is crucial in meeting nutrient requirements of poultry. This aims at avoiding excess nutrient supply as much as nutrient deficiency. Advances in this regard are made possible by computer software developers. Prominent among poultry feed formulation software is the Least-Cost formulation software. It is helpful in formulating high-quality diets for different types and classes of birds at a low cost. Generally, feed cost constitutes more than 60% of poultry production cost [9]. Therefore, use of this advance technique in diet formulation greatly reduce the cost of feeding birds; which may account for affordability of poultry products.

The most valuable advance technique in poultry nutrition is the use of the NIRS technology [10–12]. Apart from accurately predicting the chemical composition of raw feed ingredients and feeds, this technology enables the farmer to rapidly measure metabolizable energy (ME) and digestible amino acid (DAA) in real time (or near real time) for major feed ingredients [13–15]. ME and DAA are the main dietary components considered in poultry feed formulation. The actual ME and DAA contents of feed ingredients (e.g. different geographical locations or batches) could vary substantially from the specifications setup (matrix) in the feed formulation software leading to formulation errors. This technology is used to enhance precision feed formulation in relation to ME and DAA. The results can be obtained immediately after NIRS scanning of feed ingredients. Although NIRS equipment is expensive, all other costs to implement the technology can be reduced.

**9**

*Advances in Poultry Nutrition Research-A Review DOI: http://dx.doi.org/10.5772/intechopen.95990*

rapid routine feed quality assessments.

**4.4 Use of novel feed ingredients**

**4.5 Use of feed additives**

grains in poultry diets.

affect utilisation of nutrients.

Effective means for dietary feed to be quantified and prepared is to perform studies of digestibility and bird growth efficiency studies. This helps in feed quality assessments. Advances made with respect to determination of feed utilisation are ever-evolving. These include: Growth assay technique, *In vivo* and *In vitro* digestibility techniques, Inert marker technique, Caecetomy and Ileotomy techniques and Ileal assay technique [16–19]. The advantages of these techniques among others are high precision data, reduction in duration and cost of experimentation, less labourintensive, use of small feed samples, avoid use of live birds for experiments, and

Traditionally birds are grain feeders; however, with advent of industrial processing of food for humans, a lot of by-products have been generated and research extensively for poultry feeding [20–22]. These include cereal offals, oilseed meals, brewer's dried grains, distillers dried grain with solubles (DDGS), etc. Besides, through research, lesser used feedstuffs such as barley, rye, sorghum, cassava and grain legumes are increasingly being processed for feeding [23–28]. Furthermore, other plant resources in the wild such as false yam [29] and forages [30] are being harnessed for feeding due to advances in feed processing technologies and analytical tools. The essence of using these novel feed ingredients is to serve as alternatives for conventional feed ingredients such as maize (*Zea mays*) and animal proteins (e.g. fishmeal, meat and bone meal). This is aimed at reducing feed cost or curtailing dependency on these conventional feeds, particularly in developing economies.

Feed additives are employed in poultry diets in order to improve digestive efficiency. As a consequence, poultry productivity is enhanced. Nutritional advances in feed additives include enzymes, synthetic amino acids, commercial preparations of vitamins/trace minerals, probiotics, prebiotics and toxin binders among others. Feed enzymes are commercial enzyme products aimed at augmenting the endogenous enzymes secreted in the gut of birds when fed in the diet so as to improve availability of nutrients. Researches on enzyme usage is necessitated by wide use of vegetable proteins (e.g. legumes and oilseed meals) and some cereal

The use of vegetable proteins was in response to a total ban on the use of animal protein sources in feeds by the European Union [31]; which hitherto was the main protein source in poultry diets due to their high digestibility. However, these vegetable proteins are characterised by high levels of anti-nutritional factors such as indigestible non-starch polysaccharides, phytic acid, tannins and alkaloids; which

Besides, some feed grains such as wheat, barley, sorghum and rye contain appreciable amounts of soluble non-starch polysaccharides that can cause very viscous gut content. Hence, the advances made in feed enzyme research culminated in the use of feed enzymes to depolymerise the soluble and insoluble pectic polysaccharides [32, 33] as well as hydrolyse phytates [34] in diets containing high levels of vegetable proteins and some cereal grains. In fact, feed enzymes prevent severe imbalances of nutrients that can remain undigested and reach the large intestine; thereby creating favourable environment for pathogens and consequent disease conditions. A good number of studies involving enzymes in poultry nutrition has

**4.3 Feed utilisation**
