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This experiment was to determine effects of graded levels of defatted green microalgal biomass (DGA, Nannochloropsis oceanica) on dietary protein digestion, retention, and metabolism, and on regulations of protein synthesis and energy partitioning in broiler chickens. One-day old broiler chicks were fed a corn-soybean meal-based diet containing 0 (control), 2, 4, 8 or 16% DGA for 6 weeks (n = 6 cages/diet, 6 chicks/cage). Graded levels of dietary DGA did not affect plasma and muscle protein and(or) plasma uric acid concentrations. Additionally, DGA consumption did not affect dry matter and nitrogen digestibility or retention, nor daily nitrogen excretion, as measured by both an ingestible marker and a 3-day total excreta collection. The inclusion of 4 to 8% of DGA produced moderate elevations (0.06

SUMMARY The potential of defatted microalgae from biofuel production in animal feeding remains unclear. The objective of this experiment was to determine the metabolic and environmental impacts of a defatted green microalgal biomass (DGA, Nannochloropsis oceanica, Cellana, Kailua-Kona, HI) in broiler chick diets. Day-old chicks (total = 180) were fed the control diet containing zero, 2, 4, 8, or 16% of DGA for 6 wk to determine the optimal level of DGA inclusion. Compared with chicks fed the control diet, only those fed the 16% DGA diet had lower (P

Lysine addition to swine diets via either feed-grade lysine or protein sources costs producers. To better understand how diet affects lysine oxidation (LOX), weanling pigs were fed a control (C), high protein (HP), low protein (LP), high lysine (HL), or low lysine (LL) diets. No diet-induced alterations in lysine catabolism were detected in heart or kidney (P > 0.05). Liver lysine α-ketoglutarate reductase (LKR) (P

While feeding food-producing animals with microalgae was investigated several decades ago, this research has been reactivated by the recent exploration of microalgae as the third generation of feedstocks for biofuel production. Because the resultant defatted biomass contains high levels of protein and other nutrients, it may replace a portion of corn and soybean meal in animal diets. Our laboratory has acquired 4 types of full-fat and defatted microalgal biomass from biofuel production research (Cellana, Kailua-Kona, HI) that contain 13.9 to 38.2% crude protein and 1.5 to 9.3% crude fat. This review summarizes the safety and efficacy of supplementing 2 types of the biomass at 7.5 to 15% in the diets of weanling pigs, broiler chicks, and laying hens. Based on their responses of growth performance, egg production and quality, plasma and tissue biochemical indicators, and/or fecal chemical composition, all 3 types of animals were able to tolerate the microalgal biomass incorporation into their diets at 7.5% (on as-fed basis). Holistic analysis is also provided to explore the global potential of using the defatted microalgal biomass as a new feed ingredient in offsetting the biofuel production cost, reducing the dependence on staple crops such as corn and soybeans, decreasing greenhouse gas production of animal agriculture, and developing health value-added animal products.

Three experiments were conducted to determine if defatted diatom Staurosira sp. biomass (DFA) (Cellana, Kailua-Kona, HI, USA) from biofuel production could replace a portion of soybean meal (SBM) and (or) corn in diets for broiler chicks. In experiment 1, 2-day-old chicks were fed diets with DFA at 0% (control), 7.5% replacing SBM, or 7.5 and 10% replacing SBM and corn. Chicks fed the DFA-containing diets had lower body weight gain (P < 0.05) than the controls in the starter period. Two follow-up experiments, experiments 2 and 3, indicated that supplementing the 7.5% DFA diet (replacing SBM) with amino acids, but not exogenous protease or electrolytes, restored growth performance of chicks to the control levels. Responses of plasma and liver biomarkers and gross examination of digestive tract showed no toxicity of DFA. In conclusion, DFA could substitute for 7.5% of SBM alone, or in combination with corn, in diets for broiler chicks when appropriate amino acids are added.

The activity of lysine α -ketoglutarate reductase (LKR), the initial enzyme in the principal pathway of lysine catabolism, is a primary determinant of whole-body lysine status. Past research indicated that LKR activity was predominantly hepatic; recent in vivo data suggest that other tissues can also catabolize lysine. The hypothesis of this investigation was that lysine catabolism takes place in extrahepatic tissues in pigs and that the enzymes involved may be subject to inhibition or activation. Using mitochondria from various tissues of market-age pigs, the activities of LKR and saccharopine dehydrogenase were measured. Liver mitochondria had the highest LKR activity, and the enzyme was subject to substrate inhibition. Mitochondria from the muscle, kidney, heart, and intestinal epithelial cells all had measurable LKR activity. The LKR activity was significantly inhibited by a variety of compounds including saccharopine, α -aminoadipate, α -ketoadipate, 5-hydroxy-l-lysine, and several metals. Oxidation of 14 C-lysine to 14 CO 2 was demonstrated in mitochondria isolated from the liver, muscle, and intestinal epithelial cells. Western blotting confirmed the presence of the α -aminoadipate δ-semialdehyde synthase protein in some extrahepatic tissues. These data show a significant capacity for lysine degradation in these extrahepatic tissues, most notably in cells of the intestine and muscle. These tissues should be considered important contributors to whole-body lysine catabolism.

This study was to create an ω-3 (n-3) fatty-acid-enriched chicken product using defatted green microalgae (DGA, Nannochloropsis oceanica) biomass out of biofuel research. Hatching Ross broiler chicks were fed a corn–soybean meal diet containing 0 (control), 2, 4, 8, or 16% DGA for 6 weeks (n = 6 cages/diet). The DGA inclusion resulted in a linear (p < 0.001) increase in total n-3 fatty acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) in plasma, liver, breast, and thigh at weeks 3 and 6. The increase in the breast EPA + DHA by the 16% DGA diet reached 60-fold (p < 0.0001) over the control. The 8 and 4% DGA diets elevated (p < 0.05) liver mRNA levels of Δ-9 (88%) and Δ-6 (96) desaturases. In conclusion, 8–16% of the DGA can be added in diets for broilers to produce a n-3 fatty-acid-enriched chicken meat.

Two experiments were conducted to determine the nutritional and metabolic impacts of defatted green microalgal (Desmodesmus sp.) biomass (DGM), protease, and nonstarch polysaccharide degrading enzymes (NSPase) in diets for weanling pigs and broiler chicks. Pigs fed 10% DGM for 28 days had growth performance comparable to the controls, but 23-39% lower (P < 0.05) plasma urea nitrogen concentrations. Broilers fed 15% DGM had 16% greater (P < 0.05) gain/feed efficiency than the control (0.78 vs 0.67) over the 42 day period. Supplemental protease (0.06%) decreased (P < 0.03) plasma uric acid concentrations in pigs on day 14, whereas supplemental NSPase showed negative effects in broilers. Dietary inclusions of DGM or enzymes altered (P < 0.05-0.1) hepatic and muscle protein levels of key regulators in the mTOR pathway. In conclusion, weanling pigs and broiler chicks tolerated dietary inclusions of 10 and 15% DGM, respectively, and adding protease might help digestion.