In Vitro and In Situ Evaluation of Broccoli Wastes as Potential Feed for Ruminants.

The potential of broccoli wastes (florets and stems) as ruminant feed was analyzed using in vitro and in situ techniques. Both stems and florets had high moisture content (90.6 and 86.1%, respectively), but the stems contained (% dry matter) lower levels (p < 0.05) of crude protein (CP; 23.2 vs. 30.8%) and ether extract (2.91 vs. 6.15%) and tended to have greater sugars content (p = 0.071; 33.4 vs. 19.6%) than florets. Stems had greater in vitro dry matter rumen degradability (45.3%; 24 h incubation) and lower in vitro CP intestinal digestibility (82.7%) compared with florets (42.2 and 90.1%, respectively). Rumen degradability of protein was high (<85%) for both fractions. In a second experiment, diets including different proportions of broccoli were formulated and fermented in vitro. The replacement of 24% of conventional feeds (wheat, soybean meal and wheat bran) in a concentrate by dried broccoli increased the amount of organic matter fermented in vitro and the NH3-N concentrations of a mixed diet including 40% of the concentrate. Including dried broccoli in the diet produced only small modifications in the volatile fatty acid profile and did not affect CH4 emission.

Evaluation of Brassica Vegetables as Potential Feed for Ruminants.

The objective of this study was to analyze the chemical composition, in vitro ruminal fermentation, and intestinal digestibility of discarded samples of four Brassica vegetables: Brussels sprouts (BS), white cabbage, Savoy cabbage, and red cabbage, and to assess the effects of including increasing amounts of BS in the concentrate of a dairy sheep diet on in vitro fermentation, CH4 production, and in situ degradation of the diets. All cabbages had low dry matter content (DM; <16.5%), but their DM had high crude protein (19.5-24.8%) and sugars (27.2-41.4%) content and low neutral detergent fiber (17.5-28%) and was rapidly and extensively fermented in the rumen. Rumen degradability of protein at 12 h of in situ incubation was greater than 91.5% for all cabbages, and in vitro intestinal digestibility of protein ranged from 61.4 to 90.2%. Replacing barley, corn, and soybean meal by 24% of dried BS in the concentrate of a diet for dairy sheep (40:60 alfalfa hay:concentrate) increased in vitro diet fermentation and in situ degradability of DM and protein, and reduced in vitro CH4/total volatile fatty acid ratio. In vivo trials are necessary to confirm these results.

Influence of storage time and processing on chemical composition and in vitro ruminal fermentation of olive cake.

Olive oil extraction generates olive cake (OC) that could be used in ruminant feeding. However, the chemical composition of OC is affected by multiple factors, being therefore highly variable. The objective of this study was to analyse the influence of storage time and further processing: crude, exhausted (subjected to a second oil extraction) and cyclone (obtained from a cyclone separator) on nutritive value of OC samples. Twelve samples (six crude and six exhausted) were obtained monthly from the same pond from 1 to 6 storage months, and nine samples (three crude, three exhausted and three cyclone) were obtained monthly from a different pond from 6 to 9 months storage. Chemical composition was analysed, and OC samples were fermented in vitro with sheep rumen fluid. Increasing storage time up to 6 months decreased sugars and total soluble polyphenols content but increased fibre content in OC. Dry matter effective degradability (DMED) decreased linearly (p < 0.001) by 35.9 and 45.5% as storage time augmented from 1 to 6 months for crude and exhausted OC, respectively. Crude OC had lower DMED values than exhausted OC (averaged values 0.255 and 0.294 g/g, respectively). Both potential production and rate of gas production were lower (p ≤ 0.018) in crude compared with exhausted OC, which was attributed to the high fat content of crude OC (≥86 g/kg dry matter). For samples stored longer than 6 months, cyclone had greater (p < 0.05) DMED than crude and exhausted OC (averaged values 0.207, 0.164 and 0.164 g/g, respectively). The results indicate that ruminal degradability of OC is reduced with advancing storage time, but only subtle changes were observed during the first two months. Cyclone showed greater degradability than crude and exhausted OC, but differences between crude and exhausted OC became negligible after five storage months.

Nutritive Value of Tomato Pomace for Ruminants and Its Influence on In Vitro Methane Production.

The objective of this study was to determine the variability in nutritive value for ruminants of tomato pomace (TP) samples and analyze its effect on in vitro fermentation when it was included in a high-concentrate diet. Twelve TP samples were obtained from two processing plants at weekly intervals and analyzed for chemical composition, in vitro rumen fermentation, and intestinal digestibility. The chemical composition of TP did not differ between processing plants and only slight variations were observed among sampling times. Tomato pomace had a low dry matter content (<300 g/kg), a high content of neutral detergent fiber, crude protein, and ether extract (572, 160, and 82.7 g/kg dry matter on average, respectively), and was rapidly fermented in the rumen. Protein degradability at 16 h in situ incubation was 510 g/kg and in vitro intestinal digestibility of protein was low (430-475 g/kg). Replacing soybean meal and barley straw by dried TP increased the in vitro fermentation rate and the production of volatile fatty acids and reduced NH3-N concentrations without affecting CH4. In summary, TP samples showed little variability in nutritive value over sampling time and TP of up to 180 g/kg could be included in high-concentrate diets without negatively affecting rumen fermentation.

Variability in the Chemical Composition and In Vitro Ruminal Fermentation of Olive Cake By-Products.

The objective of this study was to determine the variability in the chemical composition and in vitro ruminal fermentation of olive cake (OC) by-products. Forty-two OC samples with different storage times (1⁻14 months) and processing (25 crude (COC), 9 exhausted (EOC) and 9 cyclone (CYOC)) were fermented in vitro with sheep ruminal fluid. Exhausted OC samples had a lower ether extract content than COC and CYOC (15.9, 110 and 157 g/kg dry matter (DM), respectively), but greater neutral detergent fiber (NDF; 645, 570 and 441 g/kg DM) and acid insoluble nitrogen (9.76, 8.10 and 8.05 g/kg DM) content. Exhausted OC had the greatest (p < 0.05) average gas production rate (AGPR), whereas the greatest fermented organic matter (FOM) was obtained for EOC and CYOC. The best single predictor of the AGPR was total sugars content (R² = 0.898), whereas NDF was the best one for FOM (R² = 0.767; p < 0.001). Statistical models using storage time as a predictor variable had lower accuracy and R² values than those from the chemical composition. In summary, the nutritive value of OC was highly dependent on its processing, but its ether extract content did not negatively affect ruminal fermentation parameters, which could be estimated from either carbohydrate composition or storage time.