Chemical and fermentative characteristics of agricultural byproducts and their mixtures with roughages incubated with rumen fluid from slaughtered dromedaries

Maroua Lifa,Rosella Muresu,Mohamed-Laid Haddi,Franco Tagliapietra,Matteo Guadagnin,Leonardo Sulas,Mirko Cattani,Stefano Schiavon,Lucia Bailoni,Andrea Squartini

doi:10.3906/vet-1803-20

Abstract

In pursuit of novel strategies aimed to promote animal production while exploiting agricultural residues, using the dromedary camel rumen fluid degradation capabilities combined with a gas production (GP) technique approach, we investigated the in vitro kinetic parameters and some physical and chemical characteristics of three agro-industrial byproducts (AIBP) and their mixtures with three roughages. Chemical composition, buffering capacity, apparent degradability, pH, and in vitro GP kinetic parameters were evaluated for citrus pulp, tomato peels, apple pomace, their mixtures (50:50 % DM basis) with milk thistle, crown daisy, and polyphyte hay. GP of AIBP ranged from 200 to 240 mL/g DM. Roughages produced significantly less gas whereas mixtures gave intermediate amounts of gas. Gas from AIBP evolved with significantly (P < 0.05) shorter lag time (0.33 h) compared with roughages and mixtures. Mixing roughages with AIBP significantly (P < 0.05) increased the initial and final pH. The buffering capacity significantly increased with some mixtures and decreased with some others. In conclusion, ruminal fluid from slaughtered dromedaries, like the conventional bovine inoculum, fermented the major plant polymers and can be used in in vitro degradability trials. Rapidly fermentable AIPB mixed with roughages can improve some nutritional aspects, providing dietary fiber and correcting some in vitro kinetic parameters.

Highlights

Limited availability of feeds is the main constraint for animal production for many countries and all additional resources to meet the animal needs can alleviate the production cost
Apple pomace (AP), citrus pulp (CP), and tomato peels (TP), composed by skins, pulp, seeds, damaged fruits, and vegetables not suitable for human consumption were collected from local warehouses, and one sample for each material (1 kg) was oven- dried at 60 °C until constant weight
3.1 Chemical composition The compositional values of the two low-quality spontaneously growing forages, i.e. milk thistle and crown daisy, along with those of the three industrial byproducts, i.e. tomato peels, citrus pulp, and apple pomace were previously reported for a parallel study with bovine rumen fluid incubations [4], and only additional data are reported here

Summary

Introduction

Limited availability of feeds is the main constraint for animal production for many countries and all additional resources to meet the animal needs can alleviate the production cost. Industrial processing of fruits and vegetables generates a huge amount of agro-industrial byproducts (AIBP) every year around the world and represents 30%– 50% of the initial product [1]. Many AIBP are converted in several applications such as metabolites productions, gas production in biodigestors, and substrates for various fermentations and are potentially convertible to feeds for animal production [2]. Mixing some AIBP with one another or with roughage forages can offer the possibility to correct some of their nutritional and physicochemical traits, such as unbalanced nutritional composition, low buffering capacity, and excess of gas production by ruminal fermentation. Milk thistle and crown daisy are, on the other hand, interesting examples of highly exploitable abundant wild forages in the Mediterranean area [4, 5]

Methods

Results

Conclusion