The lining of the gastrointestinal tract is the body’s largest and most vulnerable external surface. To optimise the digestion and absorption of nutrients and to defend against pathogens and toxins, the lining has an extensive repertoire of sensory mechanisms. These signal to the gut endocrine system, the nervous system, the immune system and local defence in order that digestive efficiency and gut health are optimum.

The majority of rumen bacteria are found in biofilms attached to particulate matter in digesta. These biofilms provide organised habitats for diverse but inter-dependent microbial communities that play crucial roles in feed organic-matter fermentation and in detoxification of dietary toxins. Inclusion of materials such as biochar, bentonite or charcoal in the diet, which markedly increase the surface area for biofilm attachment, may provide additional niches for the development of specific microbial consortia that can degrade potentially toxic dietary materials and, thereby, protect the host animal.

Feed is the single largest cost in animal production. The purpose of this review is to examine evidence for the role of the mitochondria in helping to drive variation in feed efficiency between individuals, breeds and species. There is some evidence that mitochondrial content and certain aspects of mitochondrial physiology, particularly in muscle tissue, are associated with high feed efficiency.

The global demand for protein is increasing and animal-based proteins are facing increasing competition from other protein sources. Artificial meat and meat substitutes such as plant, fungal, algal or insect proteins may have an enhanced capacity to respond to different market demands when compared with conventional meat production. The future of meat and protein will likely comprise a combination of conventional meat, meat substitutes and synthetic meat products, all serving different segments of the market.

Milk fat consists of different classes of fat, namely, shorter saturated fatty acids made in the mammary gland and longer fatty acids derived from the diet. Dietary unsaturated fatty acids fed to cows can decrease secretion of the former and supply more of the latter. Measurement of these fat classes in milk on a routine basis is now possible, allowing better diagnosis of feeding problems and better control of milk fat composition.

The modern diet formulation of domestic animals relies almost exclusively on the use of computer models that are developed based on our scientific knowledge of animal nutrition and management. Recent data analyses using larger datasets and advanced statistical methods suggest that some improvements are needed. However, animal nutritionists, specifically ruminant (e.g. cattle, sheep, and goats) nutritionists, must rethink old concepts and relationships before spending more resources on collecting additional data.

Low-protein diet containing high levels of synthetic amino acids is desirable to improve feed conversion and protein utilisation. Previous studies suggested that feed conversion efficiency may be enhanced by rapidly digestible protein. This review considers the importance of digestive dynamics of starch and protein, protein-bound and crystalline amino acids to develop strategies for low-protein diets in poultry.

ASKBILL is a web-based program that provides accurate forecasts to help producers better manage sheep well-being and productivity. The program uses biophysical models, customised by user inputs, localised daily weather updates and 90-day climate forecasts. The predictive functionality will be particularly useful in managing risks and production opportunities that involve the interaction of nutritional status and climatic or parasite events.

Omeprazole is commonly provided to horses to treat and prevent gastric ulcers but there is concern regarding whether it may impair mineral absorption and, thus, bone health. This study compared mineral balance and bone health parameters in five treated and five control horses. No meaningful treatment differences were seen, minimising concerns of preventative treatment for up to 2 months.

The administration of antimicrobials to poultry for growth promotion has been linked to the global health crisis of antimicrobial resistance, resulting in consumer demand for products free of antimicrobial residues. This review discusses developments in alternatives to antimicrobials for managing gut health. The findings highlight the potential for using in-feed nutraceuticals, such as probiotics and prebiotics, as alternatives to antimicrobials, to create a healthy gastrointestinal environment and prevent and treat intestinal diseases.

In breeder herds grazing phosphorus-deficient rangelands reproduction may be severely reduced by dietary deficiencies of phosphorus. The substantial body reserves of phosphorus, particularly in the skeleton, may be mobilised during pregnancy and lactation to alleviate the consequences of inadequate diet phosphorus. However, to avoid longer-term adverse effects body phosphorus reserves must be replenished later in the annual cycle.

Beef cattle in northern Australia often eat pastures that contain low amounts of phosphorus, a mineral that is required for normal growth. In this paper, we propose new markers in blood that can be tested to determine whether cattle lack phosphorus in their diet. These markers could help farmers make more informed decisions about whether they need to provide phosphorus as a diet supplement to their breeding cows.

In the present review, recent advances in the understanding of Ca and P metabolism and poultry nutrition are described. Recent data are provided in support of the proposition that current poultry diets are formulated in excess for Ca and P. The challenge in applying a lower dietary Ca and P strategy commercially is uncertainty about the appropriate dietary concentrations of bioavailable Ca and P. These should be determined by applying the direct ileal or pre-caecal approach for determining Ca and P digestibility.

Phytases release phosphorus and other minerals as well as energy and amino acids from the undigestible fractions of monogastric diets. However, their ability to perform this function is severely compromised if the concentrations of dietary calcium are higher than expected, and this is a frequent occurrence in commercial diets. Given the value of phytases now extends very much into amino acid nutrition as well as mineral, it is even more important to monitor and avoid excess calcium if resource optimisation is to be achieved.

Diets for pigs need to be formulated based on concentrations of digestible nutrients. Digestibility of amino acids, lipids, and starch is determined at the end of the small intestine and is known as ‘ileal digestibility’, but digestibility of minerals and fibre is determined as ‘total tract digestibility’. Corrections for basal endogenous losses of nutrients are necessary to obtain values that are additive in mixed diets, and values for the standardised ileal digestibility or the standardised total tract digestibility are calculated.