Fibrous feedstuffs for the nitrogen retention of growing pigs / Contribuição dos alimentos fibrosos para a retenção de nitrogênio de suínos em crescimento

The aim of this study was to measure the nitrogen (N) balance of pigs fed with lysine-limiting diets containing practical levels of wheat bran (WB) or soybean hulls (SH). Twelve pigs with average weights of 57.36±2.01 and 72.68±3.24 kg were used in trials 1 and 2, respectively. In trial 1, treatments were CT1 - control diet and WB - diet with inclusion of 15% WB. In trial 2, CT2 - control diet and SH - diet with inclusion of 6% SH. Fibrous diets increased (P<0.05) the fecal N in 63.54 and 60.55% in relation to CT1 and CT2, respectively. The urinary N was higher (P<0.05) in pigs receiving the WB diet, but was not influenced in the trial with SH. The N retention (NRET) was higher (P>0.05) in pigs ingesting the WB diet; although, when the proportion of NRET was expressed relative to N ingested (NING) there was no difference (P>0.05) between treatments. Inclusion of SH did not affect (P>0.05) the NRET when the result was expressed in absolute or proportional terms. In conclusion, inclusion of practical levels of WB and SH does not significantly affect the metabolic costs involved with nitrogen metabolism. However, only WB was able to contribute to the N balance of pigs, while the relative amount of N added by SH was fully recovered in feces.(AU)

O objetivo deste estudo foi medir o balanço de nitrogênio (N) de suínos alimentados com dietas limitantes em lisina contendo níveis práticos de inclusão de farelo de trigo (FT) ou casca de soja (CS). Foram utilizados 24 suínos machos castrados com peso médio inicial de 57,36±2,01 kg e 72,68±3,24 kg nos experimentos 1 e 2, respectivamente. No experimento 1 os tratamentos foram CT1 - dieta controle, e FT - dieta com inclusão de 15% de FT. No experimento 2 CT2 - dieta controle, e CS - dieta com inclusão de 6% CS. As dietas fibrosas aumentaram (P<0,05) o N fecal em 64,54 e 60,55% em relação a CT1 e CT2, respectivamente. O N urinário foi maior (P<0,05) nos suínos que receberam a dieta FT, mas não foi afetado no experimento com CS. A retenção de N (NRET) foi maior (P<0,05) nos suínos alimentados com a dieta FT, entretanto quando a proporção do NRET foi expressa em relação ao N ingerido (NING) não houve diferença entre os tratamentos (P<0,05). A inclusão de CS não afetou (P<0,05) a NRET quando os resultados foram expressos em termos absolutos ou proporcionais. Em conclusão, a inclusão de níveis práticos de FT ou CS não afeta significativamente o custo metabólico envolvido no metabolismo de N. Entretanto, apenas o FT foi capaz de contribuir para o balanço de N dos suínos, enquanto a quantidade N relativa a adição de CS foi totalmente recuperada nas fezes.(AU)

Red clover silage: an alternative for mitigating the impact of nitrogen excretion in ovine production systems

The objective was to quantify the flow of intestinal nutrients and nitrogen excretion and retention in sheep receiving isoproteic diets. Eight Texel x Lacaune wethers (average body weight = 25±2.5 kg) were fitted with duodenal cannula and housed in metabolic cages. Wethers were assigned to the treatments in a crossover design with two periods of 20 days each, and all feces and urine produced by the wethers were collected. The treatments consisted of two isoproteic (160 g kg−1 of crude protein on dry matter basis) diets composed of red clover (RC) or lucerne (LU; Medicago sativa) silages plus corn silage and concentrate feed. The digestible organic matter and metabolizable energy intake did not differ between treatments. The intestinal non-ammonia N (NAN) flow was 5.9 g day−1 (37%) higher in RC wethers than in those of the LU treatment. This result was a consequence of both an increase in the efficiency of microbial protein synthesis (12.7% higher) and a decrease in ruminal degradable protein (RDP) content (20% lower) of the diet. However, the increase in the intestinal NAN flow was accompanied by a reduction in intestinal digestibility of N, resulting in similar daily N retention between treatments. The reduction of RDP content was probably the main reason for reductions in N urinary excretion in RC wethers compared with those in the LU treatment, showing that RC silage may be a tool for mitigating the impact of N excretion in ovine production systems, without changes in N retention.(AU)

Fibrous feedstuffs for the nitrogen retention of growing pigs / Contribuição dos alimentos fibrosos para a retenção de nitrogênio de suínos em crescimento

ABSTRACT: The aim of this study was to measure the nitrogen (N) balance of pigs fed with lysine-limiting diets containing practical levels of wheat bran (WB) or soybean hulls (SH). Twelve pigs with average weights of 57.36±2.01 and 72.68±3.24 kg were used in trials 1 and 2, respectively. In trial 1, treatments were CT1 - control diet and WB - diet with inclusion of 15% WB. In trial 2, CT2 - control diet and SH - diet with inclusion of 6% SH. Fibrous diets increased (P<0.05) the fecal N in 63.54 and 60.55% in relation to CT1 and CT2, respectively. The urinary N was higher (P<0.05) in pigs receiving the WB diet, but was not influenced in the trial with SH. The N retention (NRET) was higher (P>0.05) in pigs ingesting the WB diet; although, when the proportion of NRET was expressed relative to N ingested (NING) there was no difference (P>0.05) between treatments. Inclusion of SH did not affect (P>0.05) the NRET when the result was expressed in absolute or proportional terms. In conclusion, inclusion of practical levels of WB and SH does not significantly affect the metabolic costs involved with nitrogen metabolism. However, only WB was able to contribute to the N balance of pigs, while the relative amount of N added by SH was fully recovered in feces.

RESUMO: O objetivo deste estudo foi medir o balanço de nitrogênio (N) de suínos alimentados com dietas limitantes em lisina contendo níveis práticos de inclusão de farelo de trigo (FT) ou casca de soja (CS). Foram utilizados 24 suínos machos castrados com peso médio inicial de 57,36±2,01 kg e 72,68±3,24 kg nos experimentos 1 e 2, respectivamente. No experimento 1 os tratamentos foram CT1 - dieta controle, e FT - dieta com inclusão de 15% de FT. No experimento 2 CT2 - dieta controle, e CS - dieta com inclusão de 6% CS. As dietas fibrosas aumentaram (P<0,05) o N fecal em 64,54 e 60,55% em relação a CT1 e CT2, respectivamente. O N urinário foi maior (P<0,05) nos suínos que receberam a dieta FT, mas não foi afetado no experimento com CS. A retenção de N (NRET) foi maior (P<0,05) nos suínos alimentados com a dieta FT, entretanto quando a proporção do NRET foi expressa em relação ao N ingerido (NING) não houve diferença entre os tratamentos (P<0,05). A inclusão de CS não afetou (P<0,05) a NRET quando os resultados foram expressos em termos absolutos ou proporcionais. Em conclusão, a inclusão de níveis práticos de FT ou CS não afeta significativamente o custo metabólico envolvido no metabolismo de N. Entretanto, apenas o FT foi capaz de contribuir para o balanço de N dos suínos, enquanto a quantidade N relativa a adição de CS foi totalmente recuperada nas fezes.

Protein requirements of collared peccary (Pecari tajacu).

A nitrogen (N) balance digestion trial was conducted to determine the protein requirement of collared peccaries (Pecari tajacu). In a 4 × 4 Latin square design, four captive adult male peccaries were fed four isoenergy diets containing four different levels of N (11.7, 16.3, 22.8, and 26.7 g N/kg of dry matter-DM). After 15 days of adaptation, a total collection of feces and urine was carried out for five consecutive days. Regression analyses between N intake and N in feces and urine allowed to calculate the metabolic fecal nitrogen (MFN = 2.3 g N/kg of dry matter intake-DMI) and daily endogenous urinary N (EUN = 185 mg N/kg0.75). Likewise, by regression analyses between consumption of nitrogen and the nitrogen balance (NB = N ingested - N excreted, mg N/kg0.75), a daily requirement of 514 mg N/kg0.75 was calculated. Therefore, if food intake is unrestricted, collared peccaries require a minimum in their diet of about 5.4% crude protein on DM basis. These values are almost as low as those found for browsing and frugivorous wild ruminants, which reinforce the proposition that peccaries' digestive physiology is nearer to that of domestic and wild ruminants than domestic pigs. This relatively low protein requirement of collared peccary and its great ability to digest protein reveal the relevance of the forestomach for the species on nitrogen/protein metabolism and allow the use of diets with lower crude protein levels than the commercial ones used for the domestic pig, which reduces feed costs.

Nitrogen requirements of white-lipped peccary (Mammalia, Tayassuidae).

A study was conducted to determine the protein requirement of the white-lipped peccary (Tayassu pecari) performing a nitrogen (N) balance digestion trial. In a 4 × 4 Latin square design, four adult captive male peccaries were fed four isoenergetic diets containing four different levels of N (13.3, 19.2, 28.7, and 37.1 g N/kg dry matter). After 15 days of adaptation, the total collection of feces and urine was carried out for five consecutive days. By regression analysis between N intake and N in feces and urine, the metabolic fecal nitrogen (MFN = 3.1 g/kg of dry matter intake) and daily endogenous urinary N (EUN = 91.0 mg/kg(0.75) ) were determined. Likewise, by regression analyses between consumption of nitrogen and the nitrogen balance [NBN consumed-(fecal N + Urine N)] we estimated the daily requirement of 336.5 mgN/kg(0.75) . Therefore, if food intake is unrestricted, white-lipped peccaries require a minimum content in their diet of about 4.5% crude protein as percentage of dry diet. These values are similar to those found in frugivorous wild ruminants, which reinforces the proposition that peccaries have a digestive physiology nearer to that of ruminants than of domestic pigs. Furthermore, the low nutritional maintenance requirements for white-lipped peccary may explain how this species thrive in the Neo-tropical region eating predominantly palm-fruits that normally have low crude protein contents.