**5. Fodder beet pomace**

Fodder beetroot belongs to the Chenopdiaceae family, which is native to the temperate region of Europe and was obtained from a cross between white and red garden beet [55] (**Figure 8**). Fodder beet is a plant with tuberous roots and broad leaves in some countries and is considered one of the most important winter fodder sources for feeding livestock, especially dairy cows [56].

Fodder beet has a high digestibility, so its organic matter digestibility is reported to be 87–90%. It has been reported that the net energy of lactation is 7.9 to 8.2 MJ/kg of dry matter, which is equal to or even more than cereal grains [57]. In an experiment with the substitution of 24% beet pomace with barley in diets based on straw fodder in Merino fattening lambs, it was shown that the consumption of concentrate and daily weight gain in the control diet (100% barley) was more than the diet containing beet pomace [58]. Also, dairy cows fed alfalfa or silage grass had lower milk urea and lower urea or creatinine concentrations in their urine when fodder beet was added to their diet [59]. During storage, beets continue to decrease in quality and are prone to spoilage and decay due to high humidity and sugar. However, in some countries, beets are ensiled with other forages to preserve their nutritional value for cattle [60].

#### **6. Olive pomace**

Olive (Olea europaea L.) is a small tree of the Oleaceae family, which is widely cultivated in the Mediterranean region. After extracting oil from olives, that is used in food preparation [61], a significant amount of olive pomace is obtained, which includes the peel, fruit, core, fleshy part of the fruit, and the shell of the wooden core (about 25% of the weight of the olive product) (**Figure 9**) [62].

Olive pomace, that is obtained by extracting oil from olive fruit, has a lot of fat and moisture, so with the drying process, its moisture content decreases [63]. Olive *New Advances in Postharvest Technology: An Overview for Feed Production from Postharvest… DOI: http://dx.doi.org/10.5772/intechopen.111539*

**Figure 9.** *Olive plant.*

pomace also has chemical properties in terms of nutrition, with a high percentage of cellulose, hemicellulose, and lignin. It is also a good source of fatty acids, minerals, and phenolic compounds [64] (**Figure 10**). Despite having positive impacts, using olive waste as animal feed is not commercially viable because of concerns with digestion, taste, and safety [65].

Non-starch polysaccharides (NSP) are among the anti-nutritional factors found in olives that negatively affect the digestion and absorption of other nutrients. Soluble non-starch polysaccharides increase the viscosity of the contents of the gastrointestinal tract and reduce the digestibility of nutrients, while insoluble NSPs limit enzyme access to the substrate by trapping nutrients [66]. Olive pomace is less used by ruminants due to its high lignin, low crude protein, and poor digestibility compared

to forage. However, inclusion of olive pomace to the diet had a positive effect on the production and fat percentage of cow and sheep milk [67]. Several studies have been carried out on the solid-state fermentation of olive pomace using fungal strains, which allows its use as a feed additive for ruminants (cows, sheep, goats, and camels) and poultry [68, 69].

Studies have shown that the use of olive pomace in the diet of laying hens increased egg weight and shell weight, but had no effect on other functional parameters and egg quality characteristics [70, 71]. In a research study, olive pulp was used at 2.5, 5, 7.5, and 10% in preliminary and final diets of broilers, and the results showed a significant reduction in feed intake and conversion rate, which could be due to the presence of inhibitory substances in olive pulp [72]. Because of their antibacterial effect against pathogenic intestinal bacteria, phenolic compounds derived from olive leaves may be useful to broilers [73]. Additionally, broilers' digestive enzymes that alter nutrient digestibility can be stimulated or inhibited by phenolic substances [74].
