This paper reviews current knowledge on two feedstuffs, that is, insect meal and fish by-products, as alternatives to conventional animal protein sources. After an introductory part that highlights the need for sustainable development of animal production, the alternative protein sources are discussed. In particular, after providing some indications on their production and supply focussing on EU, a SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis was performed to identify the key factors that could help or impair the development of both protein sources production sectors. Finally, future perspectives are presented. The use of processed animal proteins derived from insects in farmed fish feeding is recognised by the EU legislation that authorises the use of proteins from seven insect species and the allowed substrates to rear insects. Insects have several advantages in nutritional value and the amino acid composition of their proteins generally meet animal requirements for good growth and health. The SWOT analysis indicated that insect meals can be considered as feed functional ingredients with beneficial properties that depend on the insect species, rearing system adopted, and the substrate used for their growth. Insects are expected to be increasingly used as a replacement for conventional animal-derived proteins, especially in aquafeeds. In the section regarding fishery and aquaculture by-products, the potential use of raw materials obtained during seafood processing is discussed. Peptides and amino acids recovered from as hydrolysed proteins can be used in animal feeds to partially substitute conventional protein feedstuffs thus providing nutrients, bioactive compounds and feed additives for animals. The SWOT analysis identified opportunities and weaknesses. Both the alternative protein sources are promising alternative feed ingredients for livestock production.

The expected future demand for highly nutrient animal food products will push the animal production system to search for new sources of high-quality protein feedstuffs. In this scenario, economic and environmental issues will have to be considered while reducing the competition with the plant-based human food chains. Legume grains and some oilseed cakes, by-products from the oil industry, are the main protein sources for ruminants and terrestrial monogastrics such as pigs and poultry. Their relevant role will hold in the next decades, but it is necessary to increase the diversification of sources that can be grown profitably throughout the world, including European countries. Microalgae are a promising source of protein and other nutrients for animal feeding. However, an amazing richness of biologically active substances makes these organisms very interesting as feed ingredients, as their role go far beyond the supply of nutrients. Due to the limited usage of microalgae as human foodstuffs or food ingredients, low competition between microalgae-based feed and food chains is predictable. This review aims to synthesise current knowledge on minor pulses and other protein-rich plant products and microalgae, as alternative ingredients to the conventional animal protein sources, focussing on their production, availability, and nutritional values. Points of strength, weakness, opportunity and threat related to the use of these protein sources in animal feeding are separately analysed through a SWOT approach to underlie future needs in terms of research and/or technological development that could help valorise these nutrient sources as feed ingredients.

Digestibility trials need a viable rumen fluid as inoculum to degrade feeds. The variability of rumen fluid depends on the animal’s diet, while its viability is greatly influenced by the sampling and handling procedures. In this article, we present a replicable protocol for sampling the rumen fluid from slaughtered animals for in vitro digestibility trials. A detailed list of the tools and a step-by-step standardized procedure for the collection, storage and the transportation of the rumen fluid from the slaughterhouse to the laboratory is presented. We also describe a digestibility trial for establishing the maximum storage time of rumen fluid from sampling to its use. The results show that the rumen fluid, collected and maintained according to the proposed protocol, can be stored and used from 30 to 300 min from sampling without significantly compromising the fermentative activity of the microbial population.

This review summarises the use of the Ankom Daisy^II incubator (AD^II; Ankom Technology Corporation Fairport, NY, USA), as presented in studies on digestibility, and its extension to other species apart from ruminants, from its introduction until today. This technique has been modified and adapted to allow for different types of investigations to be conducted. Researchers have studied and tested different procedures, and the main sources of variation have been found to be: the inoculum source, sample size, sample preparation, and bag type. In vitro digestibility methods, applied to the AD^II incubator, have been reviewed, the precision and accuracy of the method using the AD^II incubator have been dealt with, and comparisons with other methods have been made. Moreover, some hypotheses on the possible evolutions of this technology in non-ruminants, including pets, have been described. To date, there are no standardised protocols for the collection, storage, and transportation of rumen fluid or faeces. There is also still a need to standardise the procedures for washing the bags after digestion. Moreover, some performance metrics of the instrument (such as the reliability of the rotation mechanism of the jars) still require improvement.

Milk is recognised as an important element of the pastoral civilisations in Africa, where it has not only an economic value, but also a social and cultural value. The objective of this review is to identify the main African dairy products, mainly focussing on typical production processes based on the use of local animal resources. To this aim, dairy products were classified into five categories, according to the type and the production method: fresh cheese, ripened cheese, fermented milk, butter and dairy by-products. These categories give rise to an extraordinary range of local products where tradition, culture, and environmental conditions and constraints play a major role in contributing to this diversification. In some countries, some attempts are being made in order to valorise the local dairy products by establishing Slow Food Presidia or including them in the Ark of Taste compiled by Slow Food. One of the main constraints that limits the commercialisation and export of African dairy products is related to the scarce hygiene in milk production and processing, and the frequent absence of starter cultures, which result in products with non-standardised characteristics, short shelf life and high spoilage susceptibility, with consequent risks for human health. Efforts should be made to support the dairy products chain in Africa, by making production processes safer and by valuing local resources, in order to expand the internal market and the export opportunities. Development cooperation projects may play an important role in this respect and should therefore be encouraged.

SUMMARY: The effects of yeast Saccharomyces cerevisiae, either inactivated (by osmotic pressure, designated IY) or provided as a culture containing live yeast cells (YC), on ruminal fermentation of two different diets were investigated in vitro. Total mixed rations (TMR) having forage:concentrate ratios of 0·6:0·4 (medium–high forage diet) and 0·2:0·8 (low-forage diet) were incubated in batch cultures of mixed ruminal micro-organisms to which either IY (to reach concentrations of 500 and 250 mg product/l incubation medium) or YC (at a concentration of 150 mg product/l) were added directly as powder. To evaluate the effects of the additive on ruminal microbial population, sheep used as donors of rumen fluid were allocated to three experimental groups: Control (no additive), IY and YC, that received a diet with the corresponding additive for 10 days. With both diets, YC decreased ruminal pH compared to control, whereas IY had no effect. Adding yeast products to the high-fibre diet affected total volatile fatty acid (VFA) production and VFA composition, in general with a slight increase in IY and a significantly greater increase in response to the addition of YC. Ammonia nitrogen (P=0·006), total gas production (P<0·001) and in vitro dry matter disappearance (IVD) (P<0·001) showed the highest values with YC. Methane production was higher than the control when the IY inoculum was used, and increased even more with the YC inoculum (P<0·001). With the high-concentrate TMR, no effects on total VFA concentration were observed when yeast additives were used. Similar trends were shown for lactate and methane production and total gas production, where values tended to be higher when using the YC inoculum (P values of 0·055, <0·001, 0·006 and <0·001, respectively). After 144 h of incubation, differences were observed only with the high-fibre diet in the cumulative gas production at 24 h of incubation and in the average fermentation rate, which was greater with YC, although the asymptotic gas production was not affected. These results indicate that live yeasts affect ruminal fermentation slightly more than inactivated yeasts, although both products require a regular administration and some adaptation of the ruminal microbial population for the stimulatory effects to become apparent. The effects of yeasts on ruminal fermentation are diet-dependent, being more noticeable with a high-fibre substrate, and subtle with a high-concentrate diet.